[ddouglass]

Yes files on a hard drive can get corrupted if a drive has failing sectors. However the most common problem is usually that the files (original and KMH files) have been separated. Hard drives do not last forever. If you are losing files then what you need to do is run a thorough Checkdsk on the drive to make sure your files are not in failing areas.
The initial poster was not referring to one file at a time, but with all of his ZIP files. This tells me his problem is not failing files.