some had this problem after the update to PR1.2
(there was a bug filed: https://bugs.maemo.org/show_bug.cgi?id=10411)

a reboot and respectively taking the battery out for a moment should help.

most likely it's one widget with a bug which is crashing. maybe you can find out which one.

there are some speculation and hints included:
http://talk.maemo.org/showthread.php?t=40792