A number of users are having problems getting Power Pack 2 to download and install, even if they run updates repeatedly through the Windows Home Server console.
By far, the number one reason for this issue is users who are running a beta version of Power Pack 1, most often build 1771. When you installed a beta version of Power Pack 1, you were informed that you would need to manually uninstall it in order to install the RTM version, or to install some updates to Windows Home Server. Power Pack 2 requires Power Pack 1 to be installed, and will only install if it's the RTM version. The current, pre-Power Pack 2 versions were a mix of builds 1800.0, 1800.24, and 1800.36, if I recall correctly.
So if your Windows Home Server resources show up as build 1771 in the Console, Settings screen, Resources view, please manually uninstall Power Pack 1 and then run updates through the Console until it reports there is nothing further to install.
If your resources are showing some version before 1771, you don't have Power Pack 1 installed, and are at risk of a rare but very serious data corruption bug which was fixed in Power Pack 1.
If your resources are showing build 2030, you have Power Pack 2 installed already.