jackd doesn't start (JackGraphManager.cpp error)

[breek]

17:47:06.916 Patchbay disattivato.
17:47:06.948 Resetta le statistiche.
17:47:06.958 Connessioni di ALSA cambiate.
Cannot connect to server socket err = Connessione rifiutata
Cannot connect to server socket
jack server is not running or cannot be started
17:47:06.962 Cambiamento nel grafico delle connessioni di ALSA.
17:47:23.746 JACK sta partendo...
17:47:23.746 /usr/bin/jackd -dalsa -dhw:0 -r44100 -p1024 -n2
Cannot connect to server socket err = Connessione rifiutata
Cannot connect to server socket
jack server is not running or cannot be started
17:47:23.768 JACK è stato avviato con PID=8112.
no message buffer overruns
no message buffer overruns
jackdmp 1.9.7
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2010 Grame.
jackdmp 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
JACK server starting in realtime mode with priority 10
control device hw:0
control device hw:0
audio_reservation_init
Acquire audio card Audio0
creating alsa driver ... hw:0|hw:0|1024|2|44100|0|0|nomon|swmeter|-|32bit
control device hw:0
Using ALSA driver HDA-Intel running on card 0 - HDA Intel at 0xf5ff8000 irq 57
configuring for 44100Hz, period = 1024 frames (23.2 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
17:47:30.800 Non sono riuscito ad avviare JACK come client. - Operazione fallita. - Errore di comunicazione col server JACK. Controlla la finestra dei messaggi per maggiori informazioni.
JackProcessSync::LockedTimedWait error usec = 5000000 err = Connection timed out
Driver is not running
Cannot create new client
JackSocketClientChannel read fail
Cannot open qjackctl client
jackd: ../common/JackGraphManager.cpp:45: void Jack::JackGraphManager::AssertPort(jack_port_id_t): Assertion `port_index < fPortMax' failed.
17:47:30.976 JACK è stato fermato con successo.
17:47:30.976 JACK ha crashato.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: jackd 5
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Mon May 2 17:59:10 2011
InstallationMedia: Ubuntu-Studio 11.04 "Natty Narwhal" - Release amd64 (20110426.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=it_IT:en
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: jackd-defaults
UpgradeStatus: No upgrade log present (probably fresh install)