Good point! It's probably going to be a job for the weekend, but I like the idea, thanks! At least this could help narrow things down.

Another thing I believe I forgot to mention is that this TiVo was working fine for ages, and then suddenly started having errors one day. I took it out of service, and can't remember the exact errors, but now that I think about it they could have been the same "failed to load series" errors that I am getting now on daily calls. I can't think of any condition that would suddenly cause this sort of problem, especially hardware ones.