Black Ops Map Problem?

Okay so I have my CoD Black Ops downloaded to the hardrive on my xbox to improve load speeds. Since I have done this the maps Summit,Jungle,and Radiation will load halfway and then not load anymore so I have to return to the dashboard and hope that I do not play on those maps. The map Villa will show up in the pregame lobby and it just says disk unreadable when that map is about to be played on and then returns me to the dashboard. I tried taking the game off of my hardrive but that didn't help at all. I put it back on the hardrive to improve the load speeds for the maps that do work but I really want to play on the maps I mentioned. The disk is mildly scratched here and there but there is no major scratches so I don't know what the problem is? My xbox is getting old and the drive laser sucks and it takes awhile for the disk to be read in the first place because of the drive laser but it takes awhile with all games, but it also happened to me in MW2 where I couldn't play on any of the 2nd map pack maps, I don't know if its the hardrive, the disk, or the xbox but I really would like to play on those maps. Any suggestions?