Hello hope you can help me..

I have found this script on http://www.phpeasystep.com/mysql/9.html but it dosen't update the database. I don't get any errors so i can't find out what is wrong.

UPDATE.PHP:
<?php
$host="localhost"; // Host name
$username="xx"; // Mysql username
$password="xx"; // mysql password
$db_name="xx"; // Database name
$tbl_name="test_mysql"; // Table name

// Connect to server and select database.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// get value of id that sent from address bar
$id=$_GET['id'];


// Retrieve data from database
$sql="SELECT * FROM $tbl_name WHERE id='$id'";
$result=mysql_query($sql);

$rows=mysql_fetch_array($result);
?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<form name="form1" method="post" action="update_ac.php">
<td>
<table width="100%" border="0" cellspacing="1" cellpadding="0">
<tr>
<td>&nbsp;</td>
<td colspan="3"><strong>Update data in mysql</strong> </td>
</tr>
<tr>
<td align="center">&nbsp;</td>
<td align="center">&nbsp;</td>
<td align="center">&nbsp;</td>
<td align="center">&nbsp;</td>
</tr>
<tr>
<td align="center">&nbsp;</td>
<td align="center"><strong>Name</strong></td>
<td align="center"><strong>Lastname</strong></td>
<td align="center"><strong>Email</strong></td>
</tr>
<tr>
<td>&nbsp;</td>
<td align="center"><input name="name" type="text" id="name" value="<? echo $rows['name']; ?>"></td>
<td align="center"><input name="lastname" type="text" id="lastname" value="<? echo $rows['lastname']; ?>" size="15"></td>
<td><input name="email" type="text" id="email" value="<? echo $rows['email']; ?>" size="15"></td>
</tr>
<tr>
<td>&nbsp;</td>
<td><input name="id" type="hidden" id="id" value="<? echo $rows['id']; ?>"></td>
<td align="center"><input type="submit" name="Submit" value="Submit"></td>
<td>&nbsp;</td>
</tr>
</table>
</td>
</form>
</tr>
</table>

<?

// close connection
mysql_close();

?>

UPDATE_AC.PHP:
<?php
$host="localhost"; // Host name
$username="xx"; // Mysql username
$password="xx"; // Mysql password
$db_name="xx"; // Database name
$tbl_name="test_mysql"; // Table name

// Connect to server and select database.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// update data in mysql database
$sql = "UPDATE $tbl_name SET name='$name', lastname='$lastname', email='$email' WHERE id='$id'";
$result=mysql_query($sql);

// if successfully updated.
if($result){
echo "Successful";
echo "<BR>";
echo "<a href='list_records.php'>View result</a>";
}

else {
echo "ERROR";
}

?>

LIST_RECORDS.PHP:
<?php
$host="localhost"; // Host name
$username="xx"; // Mysql username
$password="xx"; // Mysql password
$db_name="xx"; // Database name
$tbl_name="test_mysql"; // Table name

// Connect to server and select database.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

$sql="SELECT * FROM $tbl_name";
$result=mysql_query($sql);
?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<td>
<table width="400" border="1" cellspacing="0" cellpadding="3">
<tr>
<td colspan="4"><strong>List data from mysql </strong> </td>
</tr>

<tr>
<td align="center"><strong>Name</strong></td>
<td align="center"><strong>Lastname</strong></td>
<td align="center"><strong>Email</strong></td>
<td align="center"><strong>Update</strong></td>
</tr>
<?php
while($rows=mysql_fetch_array($result)){
?>
<tr>
<td><? echo $rows['name']; ?></td>
<td><? echo $rows['lastname']; ?></td>
<td><? echo $rows['email']; ?></td>

<td align="center"><a href="update.php?id=<? echo $rows['id']; ?>">update</a></td>
</tr>
<?php
}
?>
</table>
</td>
</tr>
</table>
<?php
mysql_close();
?>