If you're trying to work with MOSS 2007's IRM features, you'll find that you need to install an IRM client for the IRM server to function properly. The MOSS 2007 client can be downloaded here: http://www.microsoft.com/downloads/details.aspx?familyid=A154648C-881A-41DA-8455-042D7033372B&displaylang=en (URL may wrap)
Bill English
Mindsharp