Hello Clint -
If you were to browse into that folder path (and I hope it was along either the path <TestStand>/Adapter Support/... or <LabVIEW>/vi.lib/AddOns/TestStand/... ) is the .LLB file there? If it exists in neither of these two places then that error would indeed be a bad thing and imply that somehow the file has gone missing.
If it exists in both places, you may want to recompile both copies with LabVIEW (use the Mass Compile feature) and see if that helps one or both copies of the library be detected. The copy in the LabVIEW folder should be found first (if present), since this is the support file that is copied into LabVIEW (from TestStand) when TestStand is registered on your machine.
Regards,
Elaine R.
National Instruments
ht
tp://www.ni.com/support