Hello I installed Pd, jackd and Alsa via apt-get i have debian 5.0(lenny)

Sometimes the sound works, when work it appear an error message:

audio I/O error history:
seconds ago error type
0.14 A/D/A sync
1.00 unknown
1.52 A/D/A sync
5.76 unknown
5.76 unknown
tried but couldn't sync A/D/A
audio I/O error history:
seconds ago error type
1.40 A/D/A sync
3.38 A/D/A sync
3.69 A/D/A sync
7.12 A/D/A sync

when don't works appear this:
couldn't open MIDI input device 0
couldn't open MIDI output device 0
opened 0 MIDI input device(s) and 0 MIDI output device(s).
audio I/O error history:
seconds ago error type
4.69 unknown
4.69 unknown

thnx