NIS+-Client unable to authenticate users

A Solaris 9 NIS+ Client can't login. When a user is trying to login to an CDE-Session, it returns the error-message:

NIS+ permissions are too tight, please inform your administrator.

When I try

cat /var/adm/messages

it show's many times

authdes_seccreate: keyserv(1m) is unable to generate session key

and pam_unix_auth: NIS+ permissions require thatthe pam_dhkeys module is on the PAM stack before pam_unix_auth.

"keyserv" is not running on that mashine. If I try to start it manually i get

Illegal Instruction (core dumped)

Any suggestions? I'm at the end with my knoledge...

[645 byte] By [EmErica] at [2007-11-26 9:03:03]