It seems an odd thing to ask a UAT tester to report. Nonetheless, using Firefox, several extensions allow you to peek at the POST request. Two examples:
https://addons.mozilla.org/en-US/firefox/addon/3829/ https://addons.mozilla.org/en-US/firefox/addon/966/I don't completely remember if Firebug also allows you to view that information, but it may be the case. If you have that installed already, you can check to see what the server request and responses are in Firebug on the form page and form submission page.
For other browsers, there are probably other tools. Let us know if you need anything else.