Problem copying sounds

i have a external flash drive that i put my mpc memory card in to copy sounds to it from my computer. sometimes when i copy a lot of sounds it starts saying "error copying file or folder cannot copy (name of file): the directory cannot be created." i tried to reformat the external drive and copy everything again but then it gives me the same message with a different sound. its never the same sound twice. i also notice this problen happens once 350+ sounds have been copied to it, dont know it that has somethin to do with the problem. its kinda frustrating n i dont know what to do, anyone have any ideas? please help!!!!!!

ps all the sounds only total about 30mb and the card is 128mb so the size is not the issue.

no one has had this problem??

i've never had this issue, and i load a lot of files

maybe order them in different folders?