Is anyone else experiencing the issue? If so, then its the map creator's problem to deal with, I would guess. If not, then it could be anything. Are you getting any errors, or anything like that? Did you put everything in exports?
By the sound of it, sounds likes someone else made it. I'm a bit confused... Do you have a lot maps downloaded and/or made? Also, did you do all of this in a row? Could be anything, really. But I might like this questions answered, to try and help ya~