Hello Carlo,
We don't test Hauptwerk on any Windows Server versions (since they're very expensive and not relevant to most users), but I know of no reason that Hauptwerk v3.30 (which is compatible with Windows Vista and 7) shouldn't work properly. Although Windows Server 2008 isn't a platform that we fully support, we provide support on such platforms to the extent that we'll help with non platform-specific issues that can be reproduced on a fully supported platform (e.g. Windows 7 or Windows Vista).
However, I think it's highly likely that v3.30 would fine on Windows Server 2008.