Hi : inserting a values from External Table and Creating a purchase order by clicking the Ok Button

Hi All,

kindly help me resolve this issue !! I need to create a purch line by clicking the new purchase order !! As I mentioned !! picking external table and insert item id and revision !!

and direct inserting purchase line when you create a new purchase order !!

and I am also getting too many errors like

This purchase order line is associated with a pending invoice.
The purchase order line cannot be deleted until the pending invoices are deleted

Item identification cannot be changed when inventory transactions have been generated.

Purchase order already exits !! and can’t be created !!

how to make it works !! !! is Thanks in advance