DIRECTV2PC in Windows 7 vs Windows XP

I have two PCs which one is running Windows 7 and another one is running Windows XP. The one with Windows 7 can locate my HR23 HD DVR easily and plays every thing in my play-list but the one with Windows XP can not find the DVR. They are both connected to the same router.

It seems that I need to get latest Intel Viiv Media Share but I don't where I should get it or whether it fixes my problem.

Thanks