Document Viewer

I received a notice in Microsoft.Net Framework dialogue box :-

"An unhandled exception has occurred in a component in your application. Click continue and application will ignore this error and attempt to continue."

Object reference not set to an instance of an object,"

The Document Vewer message " Please wait while Windows configures Document Viewer..."

and asks for a missing Document Viewer.msi file.

Apparently my XP CD copies is an old version and a new one is installed in my PC. Please advise where I can get one.