New account creation generates error page

[jonpmarino]

We've had 1 report of this from users, and I've confirmed it -

To reproduce:

1. try creating a new account
2. the resulting page is an error page.

3. no confirmation email of the account is sent to user. Also, user cannot login to account, leading user to believe the account doesn't exist.

4. Yet, if I search for the account, it appears to be there:

[skorasaurus]

I had experienced the same thing when I tried to create my account a few months ago; I decided to check the issues here again to see if it had been resolved, alas. #1925