Please post the following information here and I will try to help you get this installed correctly.  When you are using a different DB owner things can get very confusing. 

1) connectionString for the SiteSqlServer in the ConnectionStrings section.

2) The following settings in the SqlDataProvider

    a) upgradeConnectionString
    c) ObjectQualifier
    b) DBOwner

3) SQL Permissions for the user that  you use in the connectionString settings.

4) Name of scheme you have setup in SQL and who is the owner of the scheme.

5) For the non aspnet objects, how are they named in the database (ex: dbo.Users, dbo.dnn_Users, mnecuser3.dnn_Users, etc).

If someone's answer gave you some help is resolvoing this, don't forget to mark the answer as providign the solution.