Yup DC. You'll need the 1.2 patch, need a link for that? Lets see if I can dig up a link for Winrar....
Winrar just download, install and you're good!
DC 1.2 Patch Download and install to your DC directory (c:/programfiles/thq/dawnofwar-darkcrusade)
Can't remember if you need the 1.1 patch to install the 1.2 patch so...
DC 1.1 Patch