HELP! new users cant register!

i just installed the country flag hack and it works fine, but when users try to register and hit the submit button on my board they get this message:

Please make sure that you have completed all the required fields. These include username, password and email. Press the back button, correct the error and try again.

and i even try testin this myself, i've filled in everything! and hit submit and i keep getting that message, can someone please help me out! ((