Error while creating standard sales order

Hi

While creating a standard sales order , I am getting a problem in the incompleteness log asking for the internal sales order no. in the 'accounting' tab of my order. It is related to cost assignment and profitability segment no.I am not able to to find the order no. for dat.

What settings should i make in spro so that this incompletion does not comes again while saving the order ? Shud i make changes at the item category level or the sales document type level or at the material master data ???