Unable to Generate Continous Purchase Orders

Hi All,

We are conducting performance testing on RMS and as a part of this we are trying to raise Domestic Purchase Orders using 20 users and business has given us the target of 2500 PO's per day,but when we try to generate PO we are getting the below mentioned error on the 52nd Order we tried to run multiple times and everytime we get the same error on the 52nd records, we checked in the DB session and found that there is no locking sessions or any locks, we are generating PO with Status as 'W' and not as Approved.we are