Why is application trying to create ASPNETDB_TMP.MDF?

Hi everyone,
I'm using the new ASP.NET Identity to manage my user roles and logins. In my SQL database I have all the necessary tables like AspNetRoles, AspNetUsers, AspNetUserRoles, etc. I am not referencing App_Data\ASPNETDB.MDF in my web.config or anywhere else in my application code. The application runs fine in my DEV environment: new users that I create are added to the AspNetUsers table, etc.
1. However, if I remove ASPNETDB.MDF and aspnetdb_log.ldf from my App_Data folder, then build and run my application, a new ASPNETDB.MDF gets re-created in App_Data. Why is this happening?
2. When I publish my application (but exclude ASPNETDB.MDF from the package), then run it in my UAT server, I get this error message when I launch the application:
Server Error in '/UAT2' Application. An error occurred during the execution of the SQL file 'InstallCommon.sql'. The SQL error number is 5123 and the SqlExc ...