The $_FILES array is where PHP stores all the information about uploaded files, rather than $_POST.

Try changing to: $userfile=$_FILES['userfile']['tmp_name'];

If you want to see what's going on with the from post try adding:

PHP: Select all

<pre>
<?
print_r($_POST);
print_r($_FILES);
?>
</pre>

This will show you what the post and files variables contain.