I did put fresh batteries in the MX-780. For the remotes I tried to learn from, after the Sony remote didn't work, I tried 3 other ones from other devices, and they didn't work either. Although they didn't have new batteries, they were all good working remotes.

When I went to teach a button, I would highlight the one I wanted in CCP, and then press the learn button on the macro dialog box. On the resulting pop-up window, I would type a description, and press learn. On the next pop-up I would wait for it to be ready, and then AS SOON as I pressed a key on the remote I wanted to learn from, the CCP window would flash timeout, and It would go back to the ready state. I could do this three times before the pop-up dialog would close back to the description / learn type pop-up. I'll try to get some screen grabs tonight to show what's happening.

I also emailed URC's tech support to see if they have any ideas. Maybe a bad remote? I just purchased it in May, so it should be under warranty still.