Can't get steamworks.NEt 7.0.0 to Work in Unity 4.6

Hi The problem is that in the title, I've downloaded steamworks.net 7.0.0 and I'm using Unity 3D 4.6.0f3, but whenever I Initialize a Build or the project I get the error:

[Steamworks.NET] Could not load [lib]steam_api.dll/so/dylib. It's likely not in the correct location. Refer to the README for more details. System.DllNotFoundException: CSteamworks at (wrapper managed-to-native) Steamworks.NativeMethods:SteamAPI_RestartAppIfNecessary (Steamworks.AppId_t) at Steamworks.SteamAPI.RestartAppIfNecessary (AppId_t unOwnAppID) [0x00005] in C:\Users\Pc\xxxxxxx\Assets\Plugins\Steamworks.NET\Steam.cs:41

And I've found no way around it, I tried copying steam_api.dll basically all over the project and nothing changes :s

Any help would be greatly appreaciated guys.