Due to the ever-growing number of spam posts on my forum from GMail accounts, I've had to disable the ability to use GMail addresses when registering for a new account on this site. If you're a (legitimate) GMail user trying to register for this site, I'm afraid you'll need to use an alternate e-mail address from now on. Existing accounts are not affected.
I apologize for the inconvenience.
Update 11/03/2009:
Apparently this was affecting existing accounts. I was just notified of this problem and removed the block. I'll need to find another way to address this. If you were having trouble logging in recently and received the error message, "The name username is registered using a reserved e-mail address and therefore could not be logged in," you should now be able to login again. Again, I apologize for the inconvenience.