If you receive HTTP 404 page not found errors on various pages, check the Application Event Log on the server and if you see a message similar to the following:
Unable to generate a temporary class (result=1).
error CS2001: Source file 'C:\Windows\TEMP\uqmnyao5.0.cs' could not be found
error CS2008: No inputs specified
Then the solution is to grant NETWORK SERVICE (the built-in Windows user that our applications run under) Full Control permissions to the C:\Windows\TEMP folder.