I would just uninstall everything and try again. It's a driver error, most likely. You can probably even leave MMC alone, just reinstall the drivers.
In fact, if you look at the PREVIOUS DRIVERS on the ATI site, look for a v6168. This is what I have come to call "the magic driver" because it tends to fix odd errors like this, where MMC refuses to cooperate.
In fact, because it's been so handy in the past, I have mirrored it in this forum, in the downloads:
http://www.digitalfaqsupport.com/uploads/t v-capture-wdm-6-13 -10-6168v1.rar
Try that.
Failing this fix, it may be a case of totally removing ATI MMC, all drivers, and manually cleaning the registry of any ATI-related info.
Sorry for the delayer response, I was unexpectedly unavailable for a short time. But I'm back now.