Crashing when opening midi

Hi.

I'm not very much experienced with Musescore. I usually run Finale on Mac OS, but I'm a fan of open-source and free software, and I'm running Ubuntu as my main (desktop) OS for half a year now, while keeping Mac OS on the laptop.

I would like to replace Finale with Musescore, as I did with most other commercial vs. free software.

But my first experience went bad.

When trying to open midi files, Musescore crashes and I have this error: "segmentation fault" (which I can see only if I run it from a terminal. From the GUI it just crashes with no error messages).

Also, when I start i from a terminal, I have the following output while starting:

PulseAudio found, but no need to suspend. Starting mscore.real...
Alsa_driver: the interface doesn't support mmap-based access.
init ALSA audio driver failed
init ALSA driver failed
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround40
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround41
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround50
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround51
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround71
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Erro de Entrada/Saída de dados(5)
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Erro de Entrada/Saída de dados(5)
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Erro de Entrada/Saída de dados(5)
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Erro de Entrada/Saída de dados(5)
ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
Cannot connect to server socket err = Ficheiro ou directoria inexistente
Cannot connect to server socket
jack server is not running or cannot be started
ALSA lib pcm.c:7316:(snd_pcm_recover) underrun occurred
Can't open "/home/carlos/.local/share/data/MusE/MuseScore/cookies.txt" to read cookies
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
illegal t2 key 0 (t1=254) subtype 0xe0000000
illegal t1 key 254 (t2=0) subtype 0xe0000000
registerPlugin: add action idx 5
Load plugin: no menu property
preferences.checkUpdateStartup: 720
lastupdate: 20.02.2012 18:38:21.335

Also note that this midi crashes only occur on Ubuntu 11.10 running on my Power Mac G4; on Mac OS running on a Macbook everything goes ok.

Any help, please?