Microsoft’s Zune software is a very good media player and the latest 4.0 update really adds some nice features. However, as with most Microsoft products, the Zune installer will check to see if your Windows Updates are enabled and then continue installing. This check prevents corporate or offline users the ability to install the new Zune 4.0 software

I attempted to install the new windows update agent, per your instructions, by using /wuforce in the command prompt.

Hello Kosh, I have experienced this problem too when I first got Vista, I turned off the UAC in User accounts in control panel in Vista & it helped. I was able to install the new updates.