Network Name Resolution Problem NetBIOS?

I have an annoying problem.

I’m using FPinger to try and draw the network. It basically pings each IP and if it gets a reply it draws a little computer for you.

The problem is that it is missing some machines.

After further investigation it seems that the ones it has problems I cannot do a ping -a to resolve the name against the IP. This is probably why FPinger is missing it.

I think this is a NetBIOS thing but am not sure. How can I
a) get the ping -a to work for all machines.
b) auto search all machines on the network.

Any ideas/suggestions would be most welcome.