Tate,
This problem was fixed several months ago. If I recall it had to do with Canon not properly writing IPTC data and subsequent editing with PM causing the TIFF table to become truncated (a case of garbage in - garbage out you might say).
I think we had a workaround for this by version 4.4.3.3 which you should definitely update to (its a free update from 4.4.3.1). Then make a copy of one of the files you are having problems with and use the Revert TIFF-based RAW to original command in the Tools menu and see if this fixes the problem. If not, you might try using the latest 4.5.1.1 version to do the revert (this worked for me from your "bad" file).
--dennis