Okay, got it working. And thanks.
This is what was going on: I have my iMac set up for two "accounts". One for my day-to-day stuff and one for my Pro Tools. When I downloaded the plug-in, I did so on the day-to-day side.
I sent the installer over to the Pro Tools side and re-installed Ultrachannel there. Bingo, my presets are in the correct folder and accessible.
What a cool plug-in! Thanks again!