You may try re-entering your verification code (Log out and log back in):
Some common mistakes:
Lower case L and One look almost the same in some fonts: 1 - l
Make sure you are entering the right one.
Zero and the capital letter O look very much the same: O - 0
Make sure you are entering the right one.
Ensure there is NO spaces or characters other than letters + numbers entered.
Enter the number [b]MANUALLY[/b], do not copy/paste. Copy/paste can sometimes add extra characters into the input field, making the code invalid.