99.9% of users are able to register successfully. Hundreds have done so this past week -- using all platforms (PC, Mac, etc) and browsers (e.g. Internet Explorer, Chrome, Firefox, Safari, Opera, etc), and for all user levels.

If you have problems, please close your browser completely, then open the registration page and register, and then close your browser again before you use a corpus. (You shouldn't have to do this, but you might try it anyway.)