When I spoke to logitech support, they were blaming Vista, but who knows. Think of it as you lost 20 bucks somewhere, and invest it on 350 module. I read someone saying 350 working flawlessly with dinovo set, and was bit skeptical about it since 355 was the newer one etc. Now that I experienced it with 350, I'm with the guy whoever said it. I have no clue why, but 350 and dinovo set works flawlessly. All the key settings work in games etc, and never went wrong since I got the system.
One thing that killed me when I had E1705 with 355 was that I would reboot, all the mouse key worked right after reboot, and I go in games or run 3dmark05, and the setpoint wouldn't even recognize any of the dinovo sets inluding the mouse. I gave up and just used the dongle myself.
When I got the M90, I remembered one guy who said 350 worked well, and gave it a try, and it does work flawlessly with 350. I have no clue why/how though.