Thanks for the quick reply. I have income and expense accounts defined for the product. I don't see any way to set a default income account in the settings menus. I have tried Settings->Configuration->Sales, Settings->Configuration->Accounting, and Company Configuration. I did try adding default income and expense accounts on the product category. Still not working.

Hi Matt, I have updated my answer with the location from where you can set the properties.

Hi Naresh, I appreciate the help. All of my products have income and expense accounts assigned. For example, "property_account_income", assigned to resource "Prototyping Materials" has account "479000 Sales". Do I need to create some new configuration parameter?

Hi Matt, Updated my answer !

Hi Matt, The reason here is that you invoice by percentage and in that case there will be no product involved that needs to make the entries so OpenERP will check for global property defined "property_account_income_categ" or accounts from fiscal position mapped. Else it will give you the configuration error ! So try to define this property and you want have that error.

Still the same error. I have done everything you describe, except that I leave Fiscal Position blank on the sales order Other Information tab.

Unfortunately your answer didn't solve my issue. I have checked if 'property_account_income_categ', and the defined 'account.account' is my XXXXXX Sales account. I also check I am using if its my main company, check,

can you all try here:http://7-0-7817.runbot.openerp.com/?db=7-0-7817-all

Thanks Naresh. Which branch should I try?

Any Green Build on 7.0 and click connect. select the database with "all" to have the demo data and then login as admin/admin

There is a more complete answer on this duplicate question: https://www.odoo.com/forum/help-1/question/create-an-invoice-for-percentage-41668