Comment 93 for bug 286285

Jakub,

What was the date/time when the system locked up? You'll want to check your logs matching up those times to help figure out why the kernel panicked.

As to the printout you provided, those look like routine firewall logs. To get help with turning that off, see http://www.ubuntu.com/support/communitysupport for different ways to get help. If I had that logging problem and couldn't find the answer by searching, I might go to http://ubuntuforums.org/forumdisplay.php?f=336 and ask.