SUSE 11.0 - "SU" command giving error for installation through YAST
 

hi ,
i am using SUSE 11.0 KDE 4.0 . My system has root user, one normal user and both are me only. I am using only 'user account' only.I used to install softwares from 'user account' by using YAST.
Now my problem is - when i am trying install a rmp file through YAST, it ask root password by a dailog window. when i entered the root password it is giving error
I had attched a screen captured image of that window.

and then after i had to be ignore that message. Installation just starts and then gives error, installation fails. so now i am not able to install any softwares through YAST !!

Two things to check are the PATH variables for yourself and root and whether the coreutils package is installed. Your system may not even run without coreutils. So maybe some commands got deleted.

Make sure that /bin/ is in your path.
Also check the permissions of su. It should be owned by root and have the suid bit set:
-rwsr-xr-x 1 root root 37320 Jun 6 2008 /bin/su

If something happened to /bin/su, try to fix it using sudo, or logging into a virtual terminal ([CTRL]-ALT-F2 for example) to fix the problem.

SUSE 11.0 - "SU" command giving error for installation through YAST
 

i had tested both of your suggestions,
they gave same output as you given.

I am getting this "su" command problem in 'user account'.Not in root account . why this is happening ??