change:
$_GET['varName']
to:
isset($_GET['varName'])?$_GET['varName']:""
This is a problem with the way Dreamweaver writes code for URL variable bindings, when you select a URL binding, Dreamweaver writes the code as:
<?php echo $_GET['varName']; ?>
more correct code would be:
<?php echo(isset($_GET['varName'])?$_GET['varName']:""); ?>