Hello!
I got the following error when trying to create a new subpage of my user page:
"User account "Heldergeovane/A" is not registered."
You can try it by yourself here:
http://en.wikipedia.org/wiki/Special:MyPage/A/B
I think the error message should not be there.
Helder
Version: unspecified
Severity: enhancement
URL: http://en.wikipedia.org/wiki/Special:MyPage/A/B