I didn't have a problem learning. However, there is an issue when doing stand alone learning (learning when the MX-900 is NOT connectecd to the PC). The remote learns the code just fine. I tested the learned codes after I learned them and they work. But when I connect the remote back up to the PC and upload the data from the remote the codes I just learned are not there.

I have identified this problem to URC as well. They claim that the codes are there but they show up in the software as a red dot instead of the green "L" for learned. In my particular case the red dot's were there but there were no codes there.

You might want to try this with your remotes and see if you come up with the same thing. Mike @ surfremote was able to duplicate the same problem that I had.