Windows update error code 66

[MalcolmY]

For the last week or so when I shut down my computer (Vista Home Premium) I get the message that I should install an Important Update. The datails of this are: Security Update for .NET Framework 4 on Windows XP, Windows Server 2003, Windows Vista, Windows 7, Windows Server 2008, Windows Server 2008 R2 for x64-based Systems (KB2160841)

Download size: 2.5 MB
You may need to restart your computer for this update to take effect.
Update type: Important

A security issue has been identified that could allow an attacker to compromise your Windows-based system that is running the Microsoft .NET Framework and gain complete control over it. You can help protect your computer by installing this update from Microsoft. After you install this item, you may have to restart your computer.

When I attempt to install this update I get an error message (Code 66A). I have two questions: Do I really need this update? and How do I overcome the error code?

[twix123]

Follow the link, then see the response of Frank Pearls, which will explain how to overcome the problem:

http://tinyurl.com/26b3hgs

[MalcolmY]

Many thanks for your reply, Twix. I followed your link and also the Frank Pearls advice. Things buzzed and whirled for several minutes and I then got a message:
Repair Did Not Succeed. Installation Suspended, Incomplete.
However when I went to Shut Down it appears that the update has been installed.????
Anyway, thanks again