You need to compile code-behind files and other class files into a binary file (assembly file), then drop it inside your sites bin folder (or make it strongly type and drop it in the GAC). *.cs files should not be on the server, only the .dll files.
This is because EPiServer uses the Web Application Project model, and not the Web site project model, where you can just drop the files inside your web sites folder, and they'll get compiled on the fly.
Hope this helps.
Frederik
That explains it. So if I compile in Visual Studio can I just replace the files in the bin-folder with the ones on the server?
Or if to put it this way: I've never worked with web application projects so what is the easiest way to go about if I want to make a small change to the site? In this example only to a couple of the files.
We've launched our site onto the public server and as the list of bugs grows I've stumbled on to a problem. When I upload code behind-files on the server the code never seems to be recompiled and I don't know if the problem lies in the IIS or in web.config. I've tried restarting the server, the site and the application pool but nothing helps. Only changes to web.config remains. Any ideas on how to fix this?