Oh, yes. Making a back up copy is a god idea. But as far as I see, file strucrture on the device is corrupted, so, that "back up" copy of corrupted files may be useless.
By the way, you should check your computer for viruses! As far as I know, some viruses can corrupt file and folder structure on attached Flash Drives. And this GPS device act as a flash drive when connected to PC, so, some viruses may attack it.