Cannot install Monitoring Services in Small Business Server 2003 R2 (MSDE install Error)

Long Story:
I installed SBS Standard fresh on this machine following a guide (http://www.msexchange.org/tutorials/Installing-and-Configuring-SBS2003.html) which recommended installing all updates to the OS before installing SBS, which I did. Apparently, this is bad since Windows Update installs incorrect versions for some items. As a result, my Companyweb site, WSUS, and Monitoring didn't work. This server is in production, so resinstalling is no longer an option.

I tried reinstalling Sharepoint a couple of times with no luck. Only this guide (http://blogs.technet.com/edwalt/archive/2006/11/29/removing-wss-3-0-companyweb-upgrade-restoring-wss-2-0-on-sbs-2003.aspx) was able to restore Sharepoint/Companyweb and WSUS. All I need now is Monitoring.

Here's the symptoms:

(screen shot 1) In Server Admin, when I click Monitoring and Reporting->Set up Monitoring Reports and Alerts, I get an error instructing me to reinstall it.
(screen shot 2) I run SBS Add/Remove, and set Server Tools to 'Maintenance' and Monitoring to 'Reinstall' (I have also tried removing/installing)
(screen shot 3) It asks for source files, which I point it to (I have the updated R2 CD, mentioned in the guide above)
(screen shot 4) Install progresses normally
(screen shot 5) Final screen shows failure, with message "MSDE 2000 Service Pack 4 did not install. For additional instructions, see the SQL Server 2000 Service Pack Web site at http://go.microsoft.com/fwlink/?LinkId=46241".

The link in the error is invalid, so no help there. I have MSDE 2000 SP4 installed, which may be the problem. I don't see anywhere to uninstall it though.

Is there a registry key somewhere that is or isn't set that needs to be? Is there a procedure that can force it? All the things I see online just say to remove and install it.
Start Free Trial