Can't install Nero DirectX not passed windows logo

I'm trying to install Nero and when it comes to installing the directX runtime I get a message "The software you are installing has not passed Windows Logo testing, the software will not be installed".

How can I switch this off, I've set driver signing to allow all but can't stop this and the PC's due to go on ebay, it's an ex business machine so I guess there's some policy in place restricting installations and as I have quite a few of them I guess they'll all be the same.

It's on XP Pro, any ideas.
Cheers