Maysa

It's really important that you (and others before you) also post the make and model of your MP3 player. There are thousands of different MP3 players around and what might have been the problem with some other brand may have nothing to do with your problem.

Also you can try and use google to see if someone else has had similar problems (maybe at another forum). Just google make and model + "Can not copy". Or Make and model + directory. Or .... + copy file. etc. etc.

BTW you don't have the little lock switch on as well ???