Beck I haven't been able to render any videos so far using the theator mode. I'm lucky that I have my HDPVR or I wouldn't be able to record anything.
On another note. If you have a game that is 10 ten minutes long...DO NOT put it in your vault to save it, thinking that you will record it later. Videos over 10 minutes in the vault will give you a Out of memory 7 error when you try to watch them. You will have to record them ASAP from theator mode. I learned this the hard way. I've lost tons of footage because of this.