I have posted a new version of my program iRiverSync. This is a free/open-source program for Windows and Mac that allows you to sync your iRiver IHP-1xx device with iTunes just like an iPod! It even automatically regenerates your database and exports playlists from iTunes, all with exactly one click!
This should fix the errors people were having with auto-detection in the last version.
You can get it at:
http://www.furiousbear.com