Order Line not assigned to compartment

 Hi,Getting following error at the time load approval:-

Steps followed:-

1.Enter Sales Order.

2. Shipment number generated.

3. Selected Vehicle.

4.Build Load

5.Approve Load.(At this stage getting following error)

Order Line not assigned to compartment  

A form level error has occurred.
Cause: The order line has not been assigned to a compartment. This is not
allowed when approving the load.
Resolution: Assign the order line to compartment or remove it from the shipment.

Please suggest the solution.

Thanks

Shakil Mulani