SuSE Linux: Versions up to (including) 7.3
The menue item System Administration
is missing in YaST.
YaST wasn't started in the installed system (as user root
in an xterm or on the console),
but was started from CD1 / boot floppy.
If you start YaST from CD (like during an installation), YaST "thinks" that you want to install or update
the system. The menue item System Administration
doesn't make much sense then.
Start YaST in the running system. The menue item System Administration
should then be visible.