by Benjamin St.Germain.
After applying the work-around, we have imported 14 courses with no problem, and plan to import dozens more this way. There really is no other solution at this point besides to wait. All that function does is "clean" the path to fix the alternating slashes and some other cleanup, but the "unclean" path works fine for the import process to access course files. If there really is a problem with the file, an error will probably the thrown somewhere else in the restore process when it tries to actually put that file into the new class.