Hi Prateek,
Lets keep it simple.
Try this
1) In NWBC Select "Processing of Multiple Objects" --> Create Mass CR for Account
2) First specify object for account ., i.e COA & ACCOUNT (You can enter the one that you face error or new one).
3) Then specify objects of Account Company code (Same COA and ACCOUNT as entered above and enter the company code".
4) Submit CR.
5) Next step you do single processing for ACCOUNT first.
6) Then try doing single processing for ACCOUNT COMPANY CODE.
You will not face the error. Try this.
Regards,
Arun