Missing Network Neighborhood

I am trying to connect someone’s laptop to their peer to peer network. I have installed NETBEUI on their laptop, and their NIC seems to be installed correctly and working fine, but Network Neighborhood is not installed, and I can’t seem to share any folders or drives. Every time I attempt to do so, I get a message, “Cannot find Access Control List.” I need to get his Nethood installed, and share his files properly. The existing network works fine. The question: What could cause this problem, and how do I correct it?