disappearing files on flash drive?

[chickens_are_good]

I have a 512mb mp3 player and my brother has a 256mb one. they are both cheap brands off ebay. they both suffer from the same problem. it doesnt happen that often, but once in a while, all the files will appear to have vanished. while in this state, if you try to write to the drive, it says that it is a read-only medium. now normally i just format mine and it is good as new (until next time), but my brother's had some important stuff on there and he wants it back. the used disk space appears correct in both windows and linux. I can mount it, but there appear to be no files in there. And yes, i have tried checking if all the files are hidden (dont know how they could all just hide themselves, but still...). any ideas? thanks in advance.

[somainertia]

I'm having this same problem. Anyone have any idea what could be causing it and how to fix it/recover the files?