Whe I try to open a configuration application or something that requieres root, I get this error.

But "su" is installing and working, within terminal off course.
Any Idea ??

my box:
Code:
Knoppix 5.1 on HD.
root@linux:/dev# uname -a
Linux linux 2.6.19 #7 SMP PREEMPT Sun Dec 17 22:01:07 CET 2006 i686 GNU/Linux