This post actually applies to many different situations in which you would automate a build on a separate server. I just happen to be familiar with Team Build. :-)
Because of how NetAdvantage deals with licensing each build server will need a full copy of NetAdvantage installed. Some customers have only copied the NetAdvantage assemblies over to their build server and will see LicenseException errors in their build reports. Even copying them into the GAC isn't enough... Just to save yourself a couple of headaches, take a few minutes to install using the product installer. There is an option in the installer to install just the assemblies and licensing components. I'd recommend deselecting all of the options if you don't need them installed on the build server. Be sure to also apply any hot fixes that your application may use as well.
As an aside, according to our current licensing agreement,
each build server you install NetAdvantage on must have a separate license whoever creates the build script must be licensed. If your team has separate build engineers, each of them should be licensed if they will be working on the build script.