No idea what the problem is about 1 to 2 weeks ago it was working, just logged into the server, saw the mod wasnt working, procceeded to update oxide, added the new spawnmini.cs download.

Before and After from console

Error while compiling: SpawnMini.cs(162,29): error CS1061: Type `BaseVehicleSeat' does not contain a definition for `GetVehicleParent' and no extension method `GetVehicleParent' of type `BaseVehicleSeat' could be found. Are you missing an assembly reference? 

Magically started working... im confused

The December Rust update broke the plugin, causing the error you pasted. The latest version of the plugin fixed it. The plugin was probably broken for you for 1-2 weeks before you noticed.

I must of thought the current cs file i had was the newer one and i just re-added it, i assume that was my problem