okay, so I've found out to add ",quota" to /etc/fstab for the filesystem
I want to have quotaized, that's been a good guess :-) ?
however, I was able to block my machine. I typed "repquota -a", and
repquota would never return. kill -9 didnt terminate the process.
typing "sync" or "df" on a differenet console would then also hang
and never return (df would only display the headers, but no fstab-contents).
additionally, "reboot" would now just kill all processes (except the
hung ones), but not really reboot the machine. You couldn`t log in
over the net, nor from the console anymore. The only way to reboot
was the <reset> key.
/herp