> - Load the 'MAME Test Drivers v0.73' datfile.
> - Go straight back to the Profiler & load the 'official mame32 cabinets'
> datfile.
> - Run a Scan & get the error.

Nope. Works fine here. Can't repeat your mentioned issue.
Take a look at the belonging .cmp files in cmpro's settings folder and check if there are wrong rompathentries in there. Or create new profiles.

And be sure you're using correct rompaths for your cabinets profile:

If you're using ZIPPED cabinet files, use:
D:\Program Files\Mame32\cabinets

If you're using UNZIPPED cabinet files, use:
D:\Program Files\Mame32


Roman Scherzer
ClrMamePro