As some have noticed, the webmail service here is a bit strange, somewhere along the way IMP decided not to show any messages in your inbox. A bit annoying to say the least. Until that is fixed, or until enough people complain that it's not as good as IMP, I have installed squirrelmail as the webmail client for users.
It works for me(tm), so it should work for you to. Please email me any issues, or a fix for IMP if you know what is going on. Squirrelmail is also available at http://mail.ufies.org for your convenience :)