I wanted to pass along the final email I received from Microsoft in regard to the issues I experienced while doing a site reset during the install of KB901034.
“The developers have confirmed that the hotfix uses preinst /stopsite. This tells site component manager to shut down everything and flag everything for reinstallation when the site reset is run. Then we restart sitecomp, and it reinstalls everything.
The reinstallation of the Reporting Point component is what resets the DCOM permissions to their defaults. The reinstallation of all components is also why we see the bootstrap service running for so long - this can vary depending on how busy a component is when Sitecomp tries to stop it.
I have modified the KB article http://support.microsoft.com/?id=901034 to include this information. It is currently visible on the web.
As to why adding the Reporting Point Users group back to the DCPM permissions might not work, I was unable to duplicate that, so it appears that there may be other factors in play. I believe it will work in most cases, as we have only received one other other call on this, and reinstalling the RP again has resolved both. I didn't document that particular scenario since we were unable to duplicate it, however I created an internal article so that our engineers are aware of the problem and solution should we get more calls. If enough calls are linked to my internal article it will be considered for a public KB article even if we can't repro in-house.
The developers have been aware of the inconvenience the across-the-board reinstallation process can cause and have implemented a fix for this in SMS 2003 SP2 which will allow hotfix developers (and end-users) to selectively reinstall a particular component rather than all of them. As to any permissions issues that result from a component reinstallation, those will have to be documented in each hotfix KB article as I have done in KB 901034.“
If you have been following the issues we experienced, then it's good that Microsoft is aware of some of the issues with the ITMU. If you have been holding off until SP2, now there will be some fixes.