CentOS - Dec 2007 - CentOS 4.5 (RHEL 4.5) - x86_64 - Login issue

Hi

Strange problem here i think but - I can ssh in to the box fine as root 
and other users eg oracle

BUT i am trying to login to the console to install oracle using X but i 
cant and i see this in the logs

hostname su(pam_unix)[20237]: session closed for user oracle

and also

hostname login[19841]: Module is unknown

so the pwd is not accepted and the connection on the console terminated 
straight away.

I have added this to my pam.d login file

session required /lib/security/pam_limits.so

So i presume this is what is causing the issue but does anyone know 
which module may be missing?

# rpm -qa | grep pam
pam_ccreds-3-3.rhel4.2
pam-0.77-66.21
pam_krb5-2.1.8-1
pam_smb-1.1.7-5
pam_passwdqc-0.7.5-2

thanks

>
>
> I have added this to my pam.d login file
>
> session required /lib/security/pam_limits.so

my bad - this is x86_64 so

session required /lib/security/pam_limits.so

should read

session required /lib64/security/pam_limits.so

thanks