Hi Ashok,
I Hope this will help you in solving the issue
1.for the Subcontracting process item category L is Mandatory. If we don't give the item Category L it will be normal Procurement process which indicates the procurement of material for stock purpose.If you have done this you have to reverse the Po and again make a PO with Item category L.then the Scenario will work fine.
2.We can edit the PO and add the Item Category ' L' and we can give the components in the Material data tab and save the PO.from there we can Follow normal Subcontracting process.
Thanks
Routhu