Undefined variable:... probleem

hey, ik heb mij een gastenboek gescreven, alles werkt, alleen krijg ik bij schrijf .php deze "fout':
Notice: Undefined variable: bericht in /home/loi/public_html/.../includes/functions.php on line 3

schrijf.php
<?

<?php
error_reporting(E_ALL);
require_once($_SERVER['DOCUMENT_ROOT'].'/.../includes/config.php');
require_once($_SERVER['DOCUMENT_ROOT'].'/.../includes/functions.php');
$ip = $_SERVER['REMOTE_ADDR'];
$datum = date("d/m/Y");
$tijd = date("H:i:s");

ban();
if(isset($_POST["submit"]))
{
if(empty($_POST["naam"]) || empty($_POST["mail"]) || empty($_POST["bericht"]) )
{
echo '<table border="0" align="center">';
echo '<tr valign="middle"><td valign="middle"><font color="#FF0000"><center>Please fill in all of the required fields</font></tr></td>';
echo '<tr valign="middle"><td valign="middle"><a href="javascript:history.go(-1)">Back</a></tr></td></table>';
}
else
{
require_once($_SERVER['DOCUMENT_ROOT'].'/.../includes/functions.php');
spam();
$_POST["naam"] = htmlspecialchars($_POST["naam"]);
$_POST["mail"] = htmlspecialchars($_POST["mail"]);
$insert = "INSERT INTO guestbook (id, ip, naam, mail, website, datum, tijd, bericht) VALUES('','$ip','$_POST[naam]','$_POST[mail]','$_POST[website]','$datum','$tijd','$bericht')";
$query = mysql_query("$insert") or die(mysql_error());
echo '<table border="0" align="center">';
echo "<tr valign=\"middle\"><td valign=\"middle\">$_POST[naam], Message successfully added to the guestbook</tr></td>";
echo "<tr valign=\"middle\"><td valign=\"middle\">You will be redirected in 3 seconds, if it does not, click <a href=\"index.php\">here</a></tr></td></table>";
echo "<META HTTP-EQUIV=\"refresh\" CONTENT=\"3\"; url=\"index.php\">";
}

}
else
{
?>
<center><a href="index.php">View the Guestbook</a></center><p></p>

<table width="450" height="150" align="center" border="0">
<tr>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':cool:');"><img src="../includes/smilies/cool.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':beer:');"><img src="../includes/smilies/beer.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':beermug:');"><img src="../includes/smilies/beermug.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':bier:');"><img src="../includes/smilies/bier.gif" border="0"></a>&nbsp;</td>

<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':devil:');"><img src="../includes/smilies/devil2.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':drums:');"><img src="../includes/smilies/drums.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':enjoy:');"><img src="../includes/smilies/enjoy.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':fdup:');"><img src="../includes/smilies/fdup.gif" border="0"></a>&nbsp;</td>
</tr>


<tr>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':fuck:');"><img src="../includes/smilies/fu.gif" border="0"></a>&nbsp;</td>
<td align="center" valign="middle"><a href="javascript:smiley();" onClick="javascript:Invoegen(':gitaar:');"><img src="../includes/smilies/guitar.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':hamer:');"><img src="../includes/smilies/hamer.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':headbang:');"><img src="../includes/smilies/headbang.gif" border="0"></a>&nbsp;</td>

<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':hippy:');"><img src="../includes/smilies/hippy.gif" border="0"></a>&nbsp;</td>
<td align="center" valign="middle"><a href="javascript:smiley();" onClick="javascript:Invoegen(':nice:');"><img src="../includes/smilies/nice.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':puke:');"><img src="../includes/smilies/puke.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':sleep:');"><img src="../includes/smilies/sleep.gif" border="0"></a>&nbsp;</td>
</tr>
<tr>
<td valign="middle" align="center" ><a href="javascript:smiley();" onClick="javascript:Invoegen(':smile:');"><img src="../includes/smilies/smile.gif" border="0"></a>&nbsp;</td>
<td align="center" valign="middle"><a href="javascript:smiley();" onClick="javascript:Invoegen(':smoke:');"><img src="../includes/smilies/smoke.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':tug:');"><img src="../includes/smilies/tug.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':wadde:');"><img src="../includes/smilies/wadde.gif" border="0"></a>&nbsp;</td>

<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':metal:');"><img src="../includes/smilies/metal.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':hit:');"><img src="../includes/smilies/hit.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':kruis:');"><img src="../includes/smilies/crucified.gif" border="0"></a>&nbsp;</td>
<td valign="middle" align="center"><a href="javascript:smiley();" onClick="javascript:Invoegen(':sperm:');"><img src="../includes/smilies/sperm.gif" border="0"></a>&nbsp;</td>

</tr>

</td>

</table>
<br>
<form name="gschrijf" method="post" action=" <? $_SERVER['PHP_SELF'] ?> ">
<table border="0" cellpadding="2" cellspacing="2" align="center">
<tr align="center" valign="middle">
<td align="center" valign="middle">
<input type="button" value=" B " onClick="javascript:set('')" style="font-weight:bold; width: 30px" class="button">&nbsp
<input type="button" value=" i " onClick="javascript:set('')" style="font-style:italic; width: 30px" class="button">&nbsp
<input type="button" value=" u " onClick="javascript:set('')" style="text-decoration: underline; width: 30px" class="button">&nbsp;
<input type="button" value="Img" onClick="img()" style="width: 40px" class="button">&nbsp;
<input type="button" value="URL" onClick="url()" style="text-decoration: underline; width: 40px" class="button"> &nbsp;
<input type="button" value="E-mail" onClick="email()" style="width:auto" class="button">&nbsp;
</td>
</tr>
</table>&nbsp;
<table border="0" cellpadding="2" cellspacing="2" align="center">
<tr>
<td>
* Name:
</td>
<td>
<input type="text" name="naam" size="35" maxlength="30" class="txt">
</td>
</tr>
<tr>
<td>
* E-mail:
</td>
<td>
<input type="text" name="mail" size="35" maxlength="35" class="txt">
</td>
</tr>
<tr>
<td>
Website:
</td>
<td>
<input type="text" name="website" size="35" maxlength="30" class="txt">
</td>
</tr>
<tr>
<td valign="top">
* Message:
</td>
<td>
<textarea name="bericht" cols="30" rows="7" class="txt"></textarea></td>
</tr>
</table>
<table align="center">
<tr>
<td>
<input type="submit" name="submit" value="Post" class="button" align="absmiddle">
</td>
</tr>
</table>
</form>
<? } ?>
<html>
<head>
<script language="JavaScript">
function smiley() {
return;
}
function Invoegen(Smiley) {
var edit;
var HuidigeTekst = document.gschrijf.bericht.value;
edit = HuidigeTekst+Smiley+" ";
document.gschrijf.bericht.value=edit;
document.gschrijf.bericht.focus();
return;
}
function set(input) {
var text;
var DezeText = document.gschrijf.bericht.value;
text = DezeText+input+" ";
document.gschrijf.bericht.value = text;
document.gschrijf.bericht.focus();
return;
}
function img()
{
var img;
var imgResult;
var text = document.gschrijf.bericht.value;
img = prompt("enter the URL of the image");
imgResult=text+""+img+""+" ";
document.gschrijf.bericht.value = imgResult;
document.gschrijf.bericht.focus();
return;
}
function url()
{
var url;
var urlResult;
var besch ;
var text = document.gschrijf.bericht.value;
besch = prompt("Enter the description of the link:");
url = prompt("Enter the URL of the link: ",'http://');
urlResult=text+""+besch+""+" ";
document.gschrijf.bericht.value = urlResult;
document.gschrijf.bericht.focus();
return;
}
function email()
{
var mail;
var mailResult;
var text = document.gschrijf.bericht.value;
mail = prompt("Enter the E-mail: ");
mailResult=text+"[email]"+mail+"[/email]"+" ";
document.gschrijf.bericht.value = mailResult;
document.gschrijf.bericht.focus();
return;
}

</script>
<link rel="stylesheet" href="../includes/css/algemeen.css" type="text/css">
</head>


?>


functions.php
<?
//smileys
$bericht = htmlspecialchars($bericht);
$bericht = str_replace(":beer:","<img src=\"../includes/smilies/beer.gif\">",$bericht);
$bericht = str_replace(":beermug:","<img src=\"../includes/smilies/beermug.gif\">",$bericht);
$bericht = str_replace(":bier:","<img src=\"../includes/smilies/bier.gif\">",$bericht);
$bericht = str_replace(":cool:","<img src=\"../includes/smilies/cool.gif\">",$bericht);
$bericht = str_replace(":devil:","<img src=\"../includes/smilies/devil2.gif\">",$bericht);
$bericht = str_replace(":drums:","<img src=\"../includes/smilies/drums.gif\">",$bericht);
$bericht = str_replace(":enjoy:","<img src=\"../includes/smilies/enjoy.gif\">",$bericht);
$bericht = str_replace(":fdup:","<img src=\"../includes/smilies/fdup.gif\">",$bericht);
$bericht = str_replace(":fuck:","<img src=\"../includes/smilies/fu.gif\">",$bericht);
$bericht = str_replace(":gitaar:","<img src=\"../includes/smilies/guitar.gif\">",$bericht);
$bericht = str_replace(":hamer:","<img src=\"../includes/smilies/hamer.gif\">",$bericht);
$bericht = str_replace(":headbang:","<img src=\"../includes/smilies/headbang.gif\">",$bericht);
$bericht = str_replace(":hippy:","<img src=\"../includes/smilies/hippy.gif\">",$bericht);
$bericht = str_replace(":nice:","<img src=\"../includes/smilies/nice.gif\">",$bericht);
$bericht = str_replace(":puke:","<img src=\"../includes/smilies/puke.gif\">",$bericht);
$bericht = str_replace(":sleep:","<img src=\"../includes/smilies/sleep.gif\">",$bericht);
$bericht = str_replace(":smile:","<img src=\"../includes/smilies/smile.gif\">",$bericht);
$bericht = str_replace(":smoke:","<img src=\"../includes/smilies/smoke.gif\">",$bericht);
$bericht = str_replace(":tug:","<img src=\"../includes/smilies/tug.gif\">",$bericht);
$bericht = str_replace(":wadde:","<img src=\"../includes/smilies/wadde.gif\">",$bericht);
$bericht = str_replace(":metal:","<img src=\"../includes/smilies/metal.gif\">",$bericht);
$bericht = str_replace(":hit:","<img src=\"../includes/smilies/hit.gif\">",$bericht);
$bericht = str_replace(":kruis:","<img src=\"../includes/smilies/crucified.gif\">",$bericht);
$bericht = str_replace(":sperm:","<img src=\"../includes/smilies/sperm.gif\">",$bericht);

?>

weet iemand hoe ik dit oplos??


Thx