I know this has happened to me, and a partner contacted me last week and it had happened to them.  The green check  (tick for the English speaking crowd ;-) ) turns to a blue one.  This means that it is still running, but the WSUS console is now in control, not the nice things in R2.

I tried to fix it by following the info in the KB article, but it just didn't work.  I was then pointed to the blog by the SBS heros and all my questions went away once I had followed the instructions.

To get to the road to the Emerald city, go to

http://blogs.technet.com/sbs/archive/2006/07/13/441594.aspx

Why Emerald city - green check - green city... Oh, go watch the Wizard of Oz :-)

ttfn

David