cant use passwd??

Hi, I am having a very strange problem on my suse 6.3... whenever i try to change passwd for any user, i get [datatwirl@mordor datatwirl]$ passwd passwd: User not known to the underlying authentication module Max Gribov [datatwirl@mordor datatwirl]$ i can change passwd's as root for any user, but the user himself cannot change his own passwd. this applies for all users on my system, and since many of them have default passwd, it became a serious security concern as well. how come this is happening? whats screwed up - pam? passwd? my machine? and what shoud i do about this, besides closing everyone's account? thanks alot max