Enable FastCGI, not possible?

Hi, I'm trying to enable fastcgi to run a rails app following the instructions on this page:

http://wiki.dreamhost.com/Ruby_on_Rails

However, when I check the box for fastcgi and click the "Change fully hosted settings now" button - which is the only valid button for the form - I get this error:

"Error: must begin with a lower case letter"

But I didn't enter anything into the New username field. Why is it validating that field? It doesn't seem even possible to save the form unless you create a new user. Which I certainly don't want to do.

Please help. Its late, and I've gotten cranky. ;-)

Evan

FYI, same thing happens when I try to update my web directory too.