[CentOS] NIS problems

I've got a RHEL5 server acting as a NIS/NFS server, and connected one C5 
machine just fine.

I'm trying to connect another, and for the life of me, cannot figure out 
why NIS won't bind.  NFS works fine.  ypbind just hangs.  I disabled 
SELinux and the firewall.   I just cannot get it to bind.

Ideas?

Thanks.

Scott