Mark:
I may have answered my own question by entering in the following into
the proxy bypass window in the Network System Preferences:
www.microsoft.com/mac/downloads.aspx?pid=download&location=/mac/download/
The problem was that since we started using a web proxy, we have had to
use bypass settings in order to facilitate the Auto Update features of
various applications suites, most notably Adobe Creative Suite and
Office 2004. The above URL is allowing users to once again download and
install the current Office 11.2.5 update through Microsoft AutoUpdate,
rather than downloading from the Mactopia site.