This is most likely a crach in compiz.
I think i saw a similar report not long ago but doesn't seem to be able
to find it.
** Package changed: ubuntu = compiz (Ubuntu)
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After update, metacity / compiz isn't started automatically anymore
https://bugs.launchpad.net/bugs/560065
You received
*** This bug is a duplicate of bug 558998 ***
https://bugs.launchpad.net/bugs/558998
** This bug has been marked a duplicate of bug 558998
[lucid] compiz-gnome broken because of metacity update
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After update, metacity / compiz isn't started automatically anymore
** Attachment added: BootDmesg.txt
http://launchpadlibrarian.net/43686566/BootDmesg.txt
** Attachment added: CurrentDmesg.txt
http://launchpadlibrarian.net/43686567/CurrentDmesg.txt
** Attachment added: Dependencies.txt
http://launchpadlibrarian.net/43686568/Dependencies.txt
**
