"Portal file xxxxxx does not exist...."
This can be a tough one. If the error causing it is clearly named in the .log of the compile with coordinates, then it is easy to fix. However, if the error is not showing up, it is time to go hunting. You could look at Token too large or some of the other errors. Check your Sky environment name, Wad count, ect. You may even try reinstalling a new copy of the compile tools in case they got corrupted, it has happened!