Yes, I had similar error with my firefox. I was making up a name for anonymous user when I tried to submit it I got an error saying that I had disallowed characters, and I shoud use [a-z][0-9] But this is exactly what I had. So after several tries I cleared the field and retyped exactly the same name and it went through. Weird. Also it says use _ instead of space, I put space and it went trough, I wonder if this is a bug?
