Using the tools in MS Expresstion I've created a Registration and Log In page. The application runs great on the "preview" Expression server, but when uploaded to the web server I receive the following errror message:

Invalid value for key 'attachdbfilename'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: Invalid value for key 'attachdbfilename'.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

I believed the Expression tools would create a database automically;  help!