I think this is more of a widespread problem. When I purchased my DSM-750, my first unit also had the same problem. Remote didn't work. I had to send it back for a replacement, which was fine. I've seen a few other reports on this forum and elsewhere that have the same issue.
I know for sure it was the 1st unit itself that didn't work, and not the remote. I have a HP MCE laptop with a remote, and the supplied remote with the DSM-750 controlled the laptop. Perhaps it's a sensor problem on the unit itself.