The long and short of it is that to install some features on Windows Server, it looks like you need to disable the User Access Control (UAC) first. The steps to disable it are (as given in the aforementioned link):
1. Go to Control panel and click User Accounts
2. Select User Accounts and click Turn User Account Control on/ Off
3. Un-check the check box beside User Account Control
4. Close the User Account Window, reboot the computer and try to install your feature again
These steps worked beautifully for me and allowed me to proceed with installing and configuring NLB for my servers. As was mentioned in the blog as well, once you have installed your features, it is safe to re-enable UAC on your servers if you would like.
The moral of the story, if something isn’t working quite right in Windows Server 2008, try disabling UAC before you try anything else.