I had my site (prebuilt/downlaoded SQLite edition) running fine on IIS6. I copied everything to a new IIS7 server, migrated the config, saw this:

C:\> %SystemRoot%\system32\inetsrv\appcmd migrate config "www.mysite.com"
Successfully migrated section "system.web/httpModules".
Successfully migrated section "system.web/httpHandlers".

And now the site says this when the home page is hit:

Object reference not set to an instance of an object.
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.NullReferenceException: Object reference not set to an instance of an object.

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.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
System.Web.HttpApplication.set_AsyncResult(HttpAsyncResult value) +40
System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +95
System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +436

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Version Information: Microsoft .NET Framework Version:2.0.50727.1434; ASP.NET Version:2.0.50727.1434