Issue in two subsequent call transaction of VA01 & VBL1N

Hi Freiends,

In a single program we are trying to create sales order,delivery note and PGI one after the other for each record from the inbound file. We are doing all the 3 process using call transaction method. After the sales order creation the sy-subrc is set to 0 but while creting the delivery note the table was not updated with the sales order number.Some time gap is required between these two process or what then how the first call transaction sets the sy-subrc to 0.

Please help to solve this problem.