Thanks Bruce, but that's not it. I did just as you said (actually I had already done that, but I tried it all again to be sure) and still got the same result.

Technically my cmd line is like:
C:\PBP>pbpw -v -ampasmwin -p18F2455 C:\PBP\USB18\USBMOUSE

but I think using the path is an insignificant difference.

I did notice something that was not in my original post. When I complie USBMOUSE.BAS with Microcode Studio it creates a USBMOUSE.MAC file and seems to copy the needed macros from PBPUSB18.MAC into it. When I compile from the command line this does not happen. Maybe because it doesn't get to that step before the failure or maybe because that step is the failure. Any insights on this?

And I should add that I have gotten the patch for v2.46 from Melabs and reinstalled fresh and all that.

Thanks again