A few important SCOM KB Articles were released

I ran into this one myself with a new installation and ended up just re-installing the database clean. This would have helped!

KB946421 – The Root Management Server encryption key is unavailable after you replace or reinstall the Root Management Server server in Microsoft System Center Operations Manager 2007

KB946417 – When you restart Root Management Server, the Health Service does not start in System Center Operations Manager 2007