Hello!

> yesterday i installed a new harddirsk into my hp425 box and copied the /usr
> directory on it.afterwards. I wonder if this could be the reason for:

How did you do the "copy"?

/usr/bin/su needs to be set suid root:

-r-sr-xr-x  1 root  wheel  12288 Aug 16 06:02 /usr/bin/su
---^

You can make it suid root again via `chmod 4555 /usr/bin/su`
but I fear while your copy you broke other permissions too.

Greets
-- 
   Name  : Thorsten Frueauf            Milano@irc cri@onaliM       //
   E-Mail: s_frueau@ira.uka.de oder ukfy@rz.uni-karlsruhe.de     \X/