I've got a working website on my local development machine.  Deployed it to my IIS6 server and when I try to access the site in a browser on the server, I get the following error:
http://localhost/prod/default.aspx
"Server Error in '/Production' Application", and in the list of web.config lines the red line was "<compilation defug="true" targetFramework="4.0">
The application was built as .NET 4.0

IIS6:
Website name: Prod
IP Address:  All Unassigned
TCP Port: 80

ASP.NET Version: 4.0.30319
Application Pool: ProdAppPool
Application Name: ProdApp
IIS 6.0 was restarted numerous times by restarting the IIS Admin Service which re-started other services as well.
The app gives me no errors when running it in VS 2010 using F5 debugging.

One thing to note which I believe is significant:  The version information ...