Asp.Net membership, create user fails

Hi All,

I created a first project with a web application with asp.net membership, everything worked out fine.

Then, I started a new project, and copied the first web application to the new project;
I changed the connection strings in the web.config, and tried to create users/roles for this new application.
Creating roles worked out just fine, however when I try to create a user, I get the following error log;


Exception information:
    Exception type: TargetInvocationException
    Exception message: Exception has been thrown by the target of an invocation.
 
Request information:
    Request URL: http://localhost:49662/asp.netwebadminfiles/security/users/adduser.aspx
    Request path: /asp.netwebadminfiles/security/users/adduser.aspx
    User host address: 127.0.0.1
    User: MuPc\User
& ...