Could not run "su" in Gnome

[Todd W.Janiak]

I am new to FreeBSD and the *nixes in general and have come a long way 
just to get a useful GUI to appear on my screen.  Now I have a hit a 
road block I can't seem to figure out.

I am running 4.10-RELEASE and the latest version of Gnome 2.6, which I 
upgraded with "portupgrade -a". When I try to change any settings under 
"System Tools" that require the admin password such as "Network 
Settings" or "Users and Groups", I receive a prompt asking me for the 
root password.  When I give it, it responds with...

Could not run "su". Make sure you have permission to access this file.

However, it will say this even if I am logged in as root.

Any ideas as to why this is happening?

Furthermore, I can't seem to auto-login with GDM as it say "Access 
Denied" when is starts. I have configure pam.conf and gdm.conf as 
recommend in the FreeBSD Gnome FAQ, A check of the logs show that 
"pam_nologin.so" cannot be found and there is no such file located in 
/usr/libs.

Any idea what package or port adds that file?

Thanks in advance for any help you might be able to give.