Cannot do Approve shipment in Transportation System is giving the Error: Shipment Route step or Load

hi all,

i couldnt able to do Approve shipmet after entering a sales order, since the system is throwing a error Shipment Route step or Load not routed when i tried to click the approve shipment button.

more information: 

 1. In the approve shipment screen the flag in Routing status field = "1" which means Routing pending.

 2. The routing entries are also fine and set up is done on Route code and Mode of transport which got picked up correctly and displaying in the approve shipment screen.

 3. the lead days are "4" and performance ratiing is "9" and only 1 route is available for this shipment, but the ship date for this order is 5/01/12 which is thursday and since the lead days are four and the delivery date is populated as