Lost the ability to learn?

Apparently my USB-UIRT suddenly lost the ability to learn.
I've been setting up some simple IR-to-RS232 stuff through IOX (a great program if your needs are simple) and earlier today I successfully learned 16 IR codes.
Then I went to set up about six more, and it stopped learning. It still receives when not in learn mode. In IOX the little learn progress bar doesn't move either, and if I remember right, that's controlled by the driver.
I downloaded lrnhelper and confirmed it, regular receive works, but learn does not. I've never used lrnhelper on a working USB-UIRT so I don't know if there is a progress bar there or not -- it looks like there is, and if there is, it doesn't move either.
I don't have any emitters attached to it, so I'm guessing the interference thing people are talking about in the other thread about it dying periodically may not apply here (or the EFI theory is wrong). I've unplugged it and plugged it back in, and I've rebooted. No effect.
What gives???
I've been setting up some simple IR-to-RS232 stuff through IOX (a great program if your needs are simple) and earlier today I successfully learned 16 IR codes.
Then I went to set up about six more, and it stopped learning. It still receives when not in learn mode. In IOX the little learn progress bar doesn't move either, and if I remember right, that's controlled by the driver.
I downloaded lrnhelper and confirmed it, regular receive works, but learn does not. I've never used lrnhelper on a working USB-UIRT so I don't know if there is a progress bar there or not -- it looks like there is, and if there is, it doesn't move either.
I don't have any emitters attached to it, so I'm guessing the interference thing people are talking about in the other thread about it dying periodically may not apply here (or the EFI theory is wrong). I've unplugged it and plugged it back in, and I've rebooted. No effect.
What gives???