Today, I got this message when I tried to access Microsoft Update on my Windows Server 2003 box. It told me that it either didn't find the control, or that it wasn't installed - and that I should look out for that yellowish bar advertising an ActiveX install attempt. Well...
After some hair pulling, Stephan pointed me to the article ActiveX controls may not load as expected in Internet Explorer due to defense in depth changes introduced in cumulative security update 896688. The downloadable olereg.vbs did the trick - WU is now back in business.