I have a PVR-350. When I dd or cat from dev0 it works and I've been using that method to record using cron jobs, but when I try to use myth to watch live TV it kills the backend and the frontend subsequently dies. When I try to record (either through myth's frontend or through mythweb the reorcding jobs don't even try to run (they show up on the schedualed recordings but not the recording scedual (or vice versa (not at that computer at the moment)). Anythoughts as to what is causing the problem?

Interesing that you'd post this under installation.... Have you checked the backed log? Does live tv work? Was MythTV properly configured? My first guess would be that /myth isn't setup...