Strange. the error isnt a technical one to do with the map, it's still the missing object/file error.
I'd say something is going horribly wrong when you're unzipping the parts of the game itself, because that error literally means map08 can't be found / is missing from the folder.
could help to check you have all the parts of the game fully downloaded and that one of the .parts didnt get cut off or corrupted, etc.
