Help: can't run jackd in realtime with FFADO

Hello, I recently upgraded my FFADO beta6 installation to beta7. This includes recompiling jackd. Install went as expected. I can run jackd in realtime with ALSA backend (had to restore audio group to limits.conf first). But I can't run jackd in realtime with firewire (ffado) backend. I can, however run it with no realtime flag. Here is the error I receive: Error (PosixThread.cpp)[ 135] Start: Cannot set create thread 22 Invalid argument I looked into udev/persistent.rules and changed raw1394 from video to audio. but that didn't seem to do anything. not sure what i'm missing here...any thoughts?