1. You
aren't running jack with realtime priorities and memory locking.
Make sure you're in the audio group, have "@audio - rtprio 99" and
"@audio - memlock unlimited" in /etc/security/limits.d/audio.conf and
start jack with a "-P 70" flag prior to "-d alsa".
As it's Ubuntu 10.10, this configuration takes place in
/etc/security/limits.d/audio.conf instead of /etc/security/limits.conf !