I have a problem in our network where our Mac's occasionally get given the wrong machine name while, I guess, getting a new DHCP lease.
The DHCP servers are Windows based - the bulk of our network is Windows, but we have some Linux machines and an increasing number of Macs. The problem specifics is that occasionally a Mac will take on the name of another machine in the network.
For example, I have a new Macbook Pro. In the OSX setup is gets called "gomez", and initially starts up on the network with that name without any problems. But after a few days when the machine was restarted (it had several restarts in the meantime), it ended up being called "florrie", which is actually the name of another machine in another part of the network.
All network ops work fine, and indeed you don't notice most of the time - it's only when you run apps like Perforce that require the hostname that you get problems.
I'm sorry I don't have more info than that, but if I know what to look for I can dig out some more facts. Or any hints on checking the network setup would be useful.