Tertius do you know how to inject?
Download Modern warfare 2 liberation v1.01. (via g00gle or so)
Open that folder. In that folder you got a map called mods.
Download this attachement (from this threadstarter) and put it in the mods folder.
Then open MW2_Liberation.exe and select at modloader your mod. (In this case QuarantinesZombieMod)