Fix possible error in Win32 error mappings.

As per the list of system error codes at http://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx, error code 124 should map to ERROR_INVALID_LEVEL.

I ran across this while trying to build my own list of error codes to check against, and do not have anything to test this change against.