I also having the same problem. I can transfer 30 games without problems except 1 game - Naruto. So i checked the filename in the folder and renamed some files so no special characters. I also delete 1 .TXT file which use Japanese font (if i'm not mistaken) as the filename.
However i can still play the game through the external. The problem only that I cannot copy to the XBox HDD which still have more than 40Gb free spaces. Anyone have the solution?