Dear Amit,
Apart from the suggestions which you've got from other valuable members, please extend the G/L in FSS0 as it seems that the G/L hasn't been yet created for your particular company code. Further, i'm sure that you're well aware of EC01 as it is used to copy already existing company code to a new one and system will copy all the possible entries from company code curreny to G/L account numbers along with other specific parameters.