Clogged cat is the first thing I thought as well until I closely examined the auto zone printout. From what it says it seems to suggest that the heater circuit isn't working in the sensor, and that what causes the code. I was thinking that a seperate code would come up for a clogged cat. I could be totally off though... It's been known to happen.

Can anyone confirm which of these two that code represents?

Edit: Did you have the same two codes?