Quoting the bug reporter:
"I did an upgrade of scrollkeeper (Woody to Sarge) and had
scrollkeeper-update started at the same time a
scrollkeeper-rebuilddb
was running from cron. I eventually had to kill
scrollkeeper-update to let
scrollkeeper-rebuilddb finish his job.
I believe scrollkeeper-* should notice it is already
running, and
should disallow or postpone."
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=258730
Thanks,