If it helps, when i download trucks for .4 all i do is click to show the file in folder view in one window and open another with the .4 vehicles folder. Then just drag and drop the folder, close both windows and done. Just open and run. And idk if you got stuck with not having the vehicle window show up or not but incase, all you should have to do is bring ur mouse to the top left and there should be a panel the comes down. So you just click get a new vehicle i think and choose.