Actual Effort for labors

I've created some tasks and assigned some resources like Mason,semi- skilled labor to this particular task and they are not employees of the organisation.
In the "Rate schedule" form under "Project costing " responsibility for the "Job" i've defined the above labors.
For the particular task,when i try to enter the Actual Effort in hours ,using the update progress button,system was throwing the error ,"required cost rate is missing" against the category of mason and semiskilled labor.
i'll be thankful if anyone help me on this issue

Oracle Applications Fusion Cloud - Inventory

Oracle Cloud/Fusion Procurement training will help you develop the fundamental skills required to set up and use the Procurement module. This training covers all the tasks, setups, forms and reports used in Procurement and related modules