Hi,
I have a feeling that you're maybe running that on NT 4.0? From what we can tell, it looks like the file "tfdll.dll" (which is a Topfield file that provides communication with the Topfield) is using setupapi.dll (which is a standard Microsoft Windows file), but the feature it's using in setupapi.dll isn't supported on NT 4.0. That would imply that the Topfield DLL doesn't support NT 4.0, which would mean that we don't either :-( Are you able to test it on an XP or 2000 machine?
Thanks,
Russell