last.fm user name merz1 not accepted

There seems to be a problem with my last.fm user name 'merz1'. It could be a problem created by last.fm itself because they switched the user account from their standard site to the German site and I am also having trouble to log in from the German site.

But when I switch to the English version (http://www.last.fm/user/merz1/) last.fm recognizes me.