Are you sure you got jack installed (sudo aptitude install jackd qjackctl)? is it running? Can you get any sound out of it?
Have you tried to make linux-alsa? does it work?
A far as I'm aware, there shouldn't be any 64-bitness in Jack. What version are you using?
Also, try chuck --probe.
Yes, Jack is working great and I have nothing but praise for the UbuntuStudio team for their work with getting pro audio and Ubuntu into the same room. My Jack version is jackd 0.103.0 and chuck --probe gives: JACK tmpdir identified as [/dev/shm] Enhanced3DNow! detected SSE2 detected [chuck]: found 1 device(s) ... JACK tmpdir identified as [/dev/shm] Enhanced3DNow! detected SSE2 detected [chuck]: ------( chuck -- dac1 )--------------- [chuck]: device name = "Jack Server" [chuck]: probe [success] ... [chuck]: # output channels = 2 [chuck]: # input channels = 2 [chuck]: # duplex Channels = 2 [chuck]: default device = YES [chuck]: natively supported data formats: [chuck]: 32-bit float [chuck]: supported sample rates: [chuck]: 48000 Hz [chuck]: [chuck]: ------( chuck -- 1 MIDI inputs )------ [chuck]: [0] : "Midi Through Port-0" [chuck]: [chuck]: ------( chuck -- 6 MIDI outputs )----- [chuck]: [0] : "Midi Through Port-0" [chuck]: [1] : "TiMidity port 0" [chuck]: [2] : "TiMidity port 1" [chuck]: [3] : "TiMidity port 2" [chuck]: [4] : "TiMidity port 3" [chuck]: [5] : "qjackctl" [chuck]: and I'm experiencing nearly identical behavior (a couple different lines but same essential messages) with 'make linux-alsa' but I really do need a jack version as my Firepod is only hosted by jack and not alsa.