I was able to find a workaround, actually. I wish I could use Toast and Mac2Tivo but a free program called pyTivoX is working for me now. It's pretty easy to setup. The files generated can be accessed under the "showcases" tab of Tivo, not in "my shows".
Hopefully Roxio can issue an update so Mac2Tivo starts working again. Until then, pyTivox will work.