Same error here, though I completed the registration hoping it would send an email.
Try this:
Flush out your cookies for the site...
Seems as if the system at times does not refresh your local/client sided cookies.
After flushing out cookies go to the site and log back in.
It should let you register or show you are registered.
99% of login and register issues can be fixed by flushing out the cookies for the site
Oneway