"Operation terminated" message

I am a fairly new user to IT and I have coming up with some issues that I am hoping to resolve.

Upon startup of IT, I receive the following message:

*Error in files:operation terminated*
Cannot find file: C\Insttext\Exchange\Medstart.glo

I am also getting this message for my DrugAdmin3 file as well.

However, they still appear in my glossary list and seem useable.

I have been saving these files on my thumbdrive every night so I can update the updated list onto my second computer. I am simply dragging these files into the InstText glossary folder and overwriting the previous. Should I not be doing it this way?

Thanks for any help you may be able to offer.