Invoice line level Project,Task,expenditure org,expenditure type is throwing error.

Hi Gurus,

We have a requirement to customize the Supplier Invoice account generator workflow (PAAPINVW) with business logic. There is no issue when we are entering the Project,Task,Expenditure Type and Expenditure Org details in the Invoice distribution form correct account is getting generated.But if the Project,Task,Expenditure Type and Expenditure Org we are entering at the line level and saving the form then nothing is happening and account is not generating. Is this because the amount field which is mandatory in distribution is not populated or there is a bug in the form. Please suggest your input. Let me know what should be