It should install it during the DTR2 installation, if you don't have it...or a higher version, but I will go look for a place to d/l it, and post the link on here,
You could just re download DTR2 and it will install Direct8X for you. And if you are worried about loosing skins and sets, just go into properties and pull out you setups and skins folder and whatever else you are not wanting to lose from the game. Then Reinstall game and just stick those folders back in.