Solution: Clean out the build and do a rebuild.
Something in the OS configuration,I don't know what, has got corrupted. Works every time for me!
Another: When building get an error that says not much more than “In” .
Solution: You’re building whilst the OS is running. Shut it down first.
Another: NMAKE : fatal error U1077: 'if' : return code '0x1' {log="C:\WINCE700.... Was trying to build OAL while OS was running. Solution: Shutdown OS and build.