.....\Steam\SteamApps\common\Company of Heroes Relaunch (the dots are for custom locations and diffrent drives, im not psychic, only psychotic)
This needs to be the final location of the Autoupdater.exe
Anywere else and it will call you a Dumbass, This is was put in as a joke but is supricingly offencive to some people.
Anyways, when you have finished downloading the installer and installed it, if the final location of the updater is not in the same location as the RelicCoh.exe it will freak out, just keep in mind that if you have the original Company of heroes that was on steam before it went on the steam servers it can get confused.
Just to put the guide in 3 easy steps but long steps
1. Download and install the installer into this Folder (.....\Steam\SteamApps\common\Company of Heroes Relaunch)
2. Register for the launcher using this link
http://forums.europeinruins.com/index.php?page=57 (keep in mind you cant use space for the launcher profice, and that the Forum and launcher accounts are diffrent, you can name them the same if you want but its up to the user)
3. run the autoupdater in admin mode and download all the updates, the installer hasnt really been updated as far as im aware of so you are going to have to download most of the files to make it up do date.
Also keep in mind Europe In Ruins is multiplayer only, it does not work in singleplayer as i dont really know, it just dosent.