Hi Malvi,
As per my experience there can be two issues.Check them both-
1. Either your BDC recording is not correct. Take the recording and run a session via SM36 with correct data and see whether the PIR is getting created successfully or not.
2. There may be some types of PIR where field NETPR is not required and is non-editable but in your BDC code you are not considering this condition and trying to pass the data everytime.
Another thing which you can do is to run the BDC in foreground mode and see behavior.
BR.