I can't find out how you generated that error. The sort order is put immediately in the query without any check (only the standard security check), so that can give these problems. That's also one of the things I'm rewriting for a next release, so there will be a check to block unvalid sort options. In a next release there will be also an ascending/descending option for a more logical sorting
I would suggest you to revert all downloads templates and reupload the files. Maybe you changed something?