I was working on rebuilding our Office Communication Server from scratch a short while ago. There were many gotcha’s in this entire process, but the one I want to touch on happened near the end of the rebuild process. The Front-End Server Service and Monitoring Agent service refused to start up, even after several reboots of the server and repairs of the installation. Errors in the event log reported the “Worker process exited prematurely” and referenced RTCHost.exe. By now, Google had become my close friend and guardian.

What happened is the update, KB967831, shuts down the Front End Server (as well as the other OCS services) to patch and then attempts to fire all the services back up.  See this article about the update.  If MSMQ is not installed, the RtcQmsAgent service (monitoring agent) will not start up, causing the Front-End server to fail. From the blog: [more]
On a good note, you can install MSMQ to get around the unfortunate "server killer" situation.

With Server 2008, you can run ServerManagerCmd -i MSMQ-Services and ServerManagerCmd -i MSMQ-Server.
With Server 2003 x64, it is a little more complex as an automation task but can be done using the details mentioned here.

The RtcQmsAgent service will no longer fail to start. At that point, you should be able to install all of the QFE1 updates successfully.
I ran those two commands (even though I thought I had already installed MSMQ earlier using the Server Manager GUI) and then attempted to start the services. Success!