Msxml 4.0

My son is trying to install Age of Empires 3 on my computer(Dimension 5151) .
It loads alright. But when you go to play it. The computer gives a n alert, MSXML 4.0 is not installed correctly. It is required to play the game.
When I try to download and install MSXML 4.0. I get a message stating that my machine has MSXML 6.0 already installed.
How do I get the game to work?
Cheers.

download this file:
http://download.microsoft.com/downlo...-US/msxml4.EXE and install it

Note that uninstall any previous versions