I fixed this problem for my mate, here's what I did:
1) plugged in H10 to pc that didn't have any iriver software on it
a) I've read if you press the "o" button on the iRiver H10 when connecting it will just connect as a usb mass storage device
2) the H10 now appears as a mass storage device
3) right click on the drive, and select format ( I choose quick format)
4) install the iRiverFirmware updater from http://iriveramerica.com/support/mtpupdate/
5) when you run the updater, it found the H10, then asked if the device was from USA or Europe, mine was from Europe
6) It stated that the iRiver firmware was v0.0, and would install v2.51 (I've seen v2.53 available on the european iriver website but could not download it).
7) proceed with installing the updated firmware
8) on the last screen it says, unplug to complete firmware update - NOTE press Finish first before unplugging
9) switching on the iRiver it 'rebooted' a few times and then when the menu appeared, I connected to the pc and just dropped some mp3 files into the music directory and all was okay.
hope this helps.