The Viking Village tutorial was made using FMOD Studio 1.08 and Unity 5. There are certain issues that can arise from migrating older projects in Unity, such as the FlyingRigidBodyFPSController_HighQulaity gameobject losing it’s Player tag and the materials (used for the footsteps script) becoming read-only.
If you want to follow along with the tutorial then I recommend downloading Unity 5 and using FMOD Studio 1.08 just to understand the tutorials as they were intended, otherwise you will need to debug various warnings and compiler errors such as this.