Trouble registering

I tried registering this am, but after I gave it all of my info, it took me to an error screen. I went back and tried again, but that time it said my email address was already in use, so I assumed the registration must have worked after all, and tried again. That time, it gave me this:

phpBB : Critical Error

User not found in IM preferences table

DEBUG MODE

SELECT * FROM phpbb_im_prefs WHERE user_id=4448

Line : 95
File : functions_im.php

Now I can't even read PriusChat as a guest anymore using my usual browser because it takes me straight to that error screen, and though I'm successfully reading it now using a different browser, it still won't let me register.

I'd really love to be able to join the forums because we're thinking of getting a Prius and I have some questions for you experienced Prius owners. My original attempt to register was with the username "Dina", but I've also tried it with other usernames since then, with no success.

Thanks for any help you can give me!