Problem putting FLAC files onto 4g Ipod

[LikeButtah]

Hey team,

First I wanna say thanks to anybody who helped make rockbox possible. I've only been using it for a few days, but its clearly awesome, and I'm so happy to be free from iTunes.

I have, however, run into some trouble. I can only seem to load a few songs at a time in FLAC, it often fails and I get a zany error like: "Cannot copy (file): The request could not be performed because of an I/O device error."

I have a reasonably good PC running windows XP, and am transferring the files via usb by dragging and dropping.

Any help would be greatly appreciated!!1

*EDIT: Problem also occurs with MP3, but less frequently.