PHP and MySQL

Evening all,

I am trying to run an update form but struggerling :(

Think my brain has had enough this weekend....

#########################################################################
Form:

<form action="update.php" method="post">
<h1><?php echo "$navLink" ?> Page</h1>
<br/><hr/><br/>
<script type="text/javascript">
TinyMCE Script
</script>
<textarea id="content_2" name="content_2" rows="11" style="width:400px">
<?php echo "$content" ?>
</textarea>
<br/><br/>
<input type="submit" name="Button" value="Update Page"/>
<input type="hidden" name="<?php $keycode ?>" value="<?php echo $keycode ?>
"/>
</form>

#########################################################################

Update.php :
<?php
include("_inc\access.inc");
$cxn = mysqli_connect ($host,$user,$passwd,$dbname)
or die ("Connection Failed");
$sql = "UPDATE contenttop SET content='$_POST[content_2]'
WHERE keycode='$_POST[keycode]'";
$result = mysqli_query($cxn,$sql)
or die ("UPDATE Failed " .mysqli_error($cxn));
?>

It doesn't seem to update the database, which is the last thing i need to
sort out before the CMS is done

Can some one assist??

DB columns:
keycode navLink content
-- 
Best regards,

Gavin C