Don't know if I've been the only one with trouble getting the firmware updater to recognize my device, but iRiver global has released a new updater that solved my problem. You can find it
here.
The version is V2.5.0.0 versus 2.2.0.0 on iRiver America's support site. This is not a firmware upgrade, but apparently fixed some recognition issues that at least I was having using my desktop with Windows XP SP2 and WMP11 (which I was strangely not having with my laptop).
Haven't seen any problems posted like this here, but I hope it helps someone.