I'm on XP Home. I just got the player this morning, first thing I did was go to put rockbox on it, which was when I first encountered the error, but avoided it, as I said previously, by extracting the zip archive from the device itself, which for some reason allowed me to use long filenames. After seeing that it wouldn't let me copy files with long filenames I tried a quick format (using the program on the CD that was bundled with the device) which didn't help. I'm assuming that this is just an error with explorer, and I'm about to try and find an alternative alternative file manager.