Okay, problem solved. BUT NOT entirely by what that info says to do.
The I-Pac was showing up with a yellow exclamation point in Device Manager.
However, the reg file was no help. I even ran the reg file, unplugged the I-Pac, shut the PC down and booted it back up and plugged the I-Pac back in. Still came back in with the yellow exclamation point.
So, with the I-Pac still plugged in, in Device Manager I right-clicked on the HID item with the yellow exclamation point and selected Uninstall to remove it. Then I unplugged the I-Pac and plugged it back and the I-Pac was redected as a new device and worked fine, even after shutting the PC down and back up.
So I loaded up WinIPac and reprogrammed it with my custom stuff again, worked fine, until I shut down the PC. After booting the PC back up again, I was back to where I started, I-Pac didn't work and yellow exclamation point in Device Manager. So I went through the procedure of uninstalling the unknown (yellow explanation point) HID device, unplugging and plugging the I-Pac back in, and it works okay now even after shutting down the PC.
So it looks like just the act of programming the I-Pac is what messed it up. But if you do the above procedure after programming it, it should be okay after that, until you have to program it again.
Thanks for the pointer to Ultimarc's web site. Even after you mentioned it was there though it took me quite a while to find it. They should have a dedicated "Support" tab at the top of their screen and move or at least link to that troubleshooting stuff from that tab.