When creating a resource plan, a cost plan is created automatically with a default type of 'Labor Capex'; however, the default type isn't being populated.
Kingston Patch 6
The CostPlan script include creates the cost plan from a resource plan and sets the default value as name is 'Labor Capex'; however, the out of box 'Labor Capex' cost type definition was removed from the customer's instance.
Import the out of box 'Labor Capex' cost type definition or create a new one with this name. Alternatively, the script include can be modified to set the default cost type to a desired cost type definition.