I changed permissions of /tmp ( cause of a script that I tried which wrote files to /tmp which I later had no access to as user )
I changed it with konqeror (file manager as super user) to group : jack (= user)
After that I couldn't start konqeror and many other programs. error message was something like : /tmp/mcop-root is set accessale to user

After reboot I couldn't login to kde anymore.

my username to login is jack

how can set permissions of /tmp right again? and what camand should I use?
I already tried : chown root /tmp but that didn't help.

It's probably very simple but at this time I cannot use knoppix anymore.
please help