The type `UnityEngine.RaycastHit2D' has been forwarded to an assembly that is not referenced. Consider adding a reference to assembly `UnityEngine.Physics2DModule, Version=*.*.*.*, Culture=neutral, PublicKeyToken=null'

You'd need to add a reference to that DLL. In a plugin, you can use the // Reference: DLLName magic comment at the top of the plugin.

Im trying to raycast from point a to point b  i think this should work?

            Vector3 p1 = position + new Vector3(0, 200f, 0);
            Vector3 p2 = position + new Vector3(0, -200f, 0);
            Vector3 diff = p2 - p1;
            RaycastHit[] hits;
            hits = Physics.RaycastAll(p1, diff, diff.magnitude, terainLayer);​

You should be able to find that dll in the server files.