That does sound like an error on your memory card. Error scanning may have just been a temporary fix, though, so after you get everything moved you might want to consider buying a new card.
Update: I may have stumbled across the solution. I put the memory card into my laptop, which shows up as the "I" drive on my computer, then, did a defrag of the "I" drive. Pictures that weren't showing and importing are now doing so, with the exception of a few from 2 specific days.
Keeping fingers crossed that this is a permanent fix because moving small groups at a time is very taxing and I can now move bigger groups of pics as I could before. Hope this is helpful to others, and, I do appreciate all the responses from those of you trying to help.
You're correct, I meant to move them to the C drive first. I wouldn't go directly to the root, though; make a directory like:
C:/temp/
If you've tried that and had an error after one specific picture, follow Fins' advice and try moving them in small groups until you find the picture that's causing the problem.