looks like it is set up correctly.
to troubleshoot the issue, we will need to make some code checnges to get som information.
1) Add the following code at line 1 to turn on error reporting:
<?php
error_reporting(E_ALL);
ini_set('display_errors','on');
?>
2) change the following line:
$WA_redirectURL = "menus_update.php?MID=[Insert_ID]";
to
$WA_redirectURL = "";
this will prevent the redirect
3) On the bindings panel, expand the uploaded files, global status binding group, and add the debug info binding to your page
4) add this code just before the </body tag:
<?php
echo("POST:");
echo("<pre>
var_dump($_POST);
echo("</pre>");
echo("Files:");
echo("<pre>
var_dump($_FILES);
echo("</pre>");
?>
and post back the results after trying an upload.
In future, compress the php file to a zip archive to send php files.