Dec 28, 2007 08:23 PM|utlandsfantomenno1|LINK
I'm not sure how you manage to connect to the correct database, you should also supply the database name in you connectionString, so add:
Database=NameOfDb if it's not supplied somewhere else.
The error you're getting might be becuase the correct asp.net membership tables haven't been installed in you db.
Not really sure here, since the error message you're getting is about user instances, and you say they're turned on.
Either way, have a look at this post
http://forums.asp.net/t/913172.aspx since that migth straighten thing out.