[Jack-Devel] Jack cannot run after re-installing

Hi, I'm trying to use Jack with an Odroid-U3. I re-installed a Debian Wheezy image which had Jack installed and was working fine with a Focusrite Scarlett 2i4 sound card. I did an "apt-get update && apt-get upgrade" and then I installed libasound2-dev and libjack-dev because I wanted to compile Pure Data from source, and these packages are necessary. After compiling Pure Data I realized that Jack had been uninstalled (no idea why), so I installed it again, along with Qjackctl, via apt-get. Now when I try to run Jack through Qjackctl, with the same sound card, Jack starts but after half a second it stops. Here are the messages I get: 20:34:15.291 Patchbay deactivated. 20:34:15.293 Statistics reset. 20:34:15.424 ALSA connection change. connect(2) call to /tmp/jack-1000/default/jack_0 failed (err=Connection refused) attempt to connect to server failed 20:34:15.443 ALSA connection graph change. 20:34:37.680 JACK is starting... 20:34:37.681 /usr/bin/jackd -dalsa -r48000 -p1024 -n2 -Xraw -D -Chw:USB -Phw:USB -i2 -o4 connect(2) call to /tmp/jack-1000/default/jack_0 failed (err=Connection refused) attempt to connect to server failed jackd 0.124.1 Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn and others. jackd comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details 20:34:37.696 JACK was started with PID=21882. JACK compiled with System V SHM support. loading driver .. apparent rate = 48000 creating alsa driver ... hw:USB|hw:USB|1024|2|48000|2| 4|nomon|swmeter|-|32bit configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods ALSA: final selected sample format for capture: 32bit integer little-endian ALSA: use 2 periods for capture ALSA: final selected sample format for playback: 32bit integer little-endian ALSA: use 2 periods for playback 20:34:39.919 JACK connection change. 20:34:39.920 Server configuration saved to "/home/odroid/.jackdrc". 20:34:39.922 Statistics reset. 20:34:39.971 Client activated. 20:34:39.977 Buffer size change (1024). 20:34:40.493 Shutdown notification. 20:34:40.495 Client deactivated. 20:34:40.497 JACK is being forced... cannot read server event (Success) cannot continue execution of the processing graph (Bad file descriptor) graph error - calling shutdown handler cannot send request type 7 to server cannot read result for request type 7 from server (Broken pipe) cannot send request type 7 to server cannot read result for request type 7 from server (Broken pipe) 20:34:40.594 JACK has crashed. 20:34:40.704 JACK was stopped Can anyone shed some light on this one? Thanks