Why is there no texture on my terrain after I build the game?

In the Unity Editor everything looks fine, but when I Build and Run the textures on my terrains disappear. I’m using Relief Terrain Pack V2 and I get the following errors in the development console:

NullReferenceException: Object reference not set to an instance of an object

-ReliefTerrain.Awake () (at E:/Unity/Projects/X/Assets/ReliefPack/Scripts/ReliefTerrain.cs:183)

Thanks for taking the time to help.

This bug has been fixed in version 2.1 (update package from assetstore)