I have the User Forms modules intalled on a site. And it seems to work fine. Fill out the form and it shows the thank you message and it saved the submission in the database. The only problem is that its not sending out emails to the recipients added in the admin.
Also check your mail logs on your server (if you have access to them) you might find something like its not going through because your server doesn't have mail setup correctly or you didn't define a from address on the host.