Fails to start

Can you please paste here the output of the following commands:

apt-cache policy libcanberra-gtk0

apt-cache policy libcanberra-gtk3-0

apt-cache policy gir1.2-gtk-2.0

When I've submitted this bug, I didn't have libcanberra-gtk0 and libcanberra-gtk3-0 installed, but trying to get this to work, I've installed it and Sysmonster still doesn't work. By the way, you should add those as a dependency for the package in the PPA.

I already had gir1.2-gtk-2.0 installed.

Here are the outputs of the commands you requested:

andrei@andrei-desktop:~/gnome-shell/install/share/glib-2.0/schemas$ apt-cache policy libcanberra-gtk0
libcanberra-gtk0:
  Installed: 0.28-0ubuntu3
  Candidate: 0.28-0ubuntu3
  Version table:
 *** 0.28-0ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ natty/main i386 Packages
        100 /var/lib/dpkg/status

apt-cache policy libcanberra-gtk3-0
libcanberra-gtk3-0:
  Installed: 0.28-0ubuntu3
  Candidate: 0.28-0ubuntu3
  Version table:
 *** 0.28-0ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ natty/main i386 Packages
        100 /var/lib/dpkg/status

andrei@andrei-desktop:~/gnome-shell/install/share/glib-2.0/schemas$ apt-cache policy gir1.2-gtk-2.0
gir1.2-gtk-2.0:
  Installed: 2.24.4-0ubuntu2
  Candidate: 2.24.4-0ubuntu2
  Version table:
 *** 2.24.4-0ubuntu2 0
        500 http://archive.ubuntu.com/ubuntu/ natty/main i386 Packages
        100 /var/lib/dpkg/status

SysMonster does not need libcanberra at all. Libcanberra is for desktop sounds and SysMonster does not produce any sounds.

I think the error messages you get does not directly relate to why SysMonster does not start but indicate some other problems.

Whatever it was, I'm not getting the libranberra error anymore after installing it, but it still doesn't start:

andrei@andrei-desktop:~$ sysmonster
/usr/lib/pymodules/python2.7/gtk-2.0/gtk/__init__.py:40: Warning: specified class size for type `PyGtkGenericCellRenderer' is smaller than the parent type's `GtkCellRenderer' class size
  from gtk import _gtk
/usr/lib/pymodules/python2.7/gtk-2.0/gtk/__init__.py:40: Warning: g_type_get_qdata: assertion `node != NULL' failed
  from gtk import _gtk
/usr/lib/pymodules/python2.7/gtk-2.0/gtk/__init__.py:40: Warning: g_ascii_strncasecmp: assertion `s2 != NULL' failed
  from gtk import _gtk
Segmentation fault

This occurs on two computers running Ubuntu 11.04 32bit.

from a similiar experience, this problem is caused by a conflict between static modules (ie pygtk) and dynamically loaded bindings (ie gi.repository).