I would check the following items:

• accounting journals
• properties for your products in sales: check that in the accounting tab of your products

This happens if the Customer you are selling to, has no Accounts Payable and Accounts Receivable tied to his profile.

To be on the safe side, configure an expense and income accounts for the Saleable Product.

The answer is already in the message. Somehow the invoice is missing an id for the account, which is a obligated field. You probably have not setup something for accounting (for example which financial book does the invoice have to be mapped in order for the financial department to process it correctly). Have you installed any financial modules and have you specified which kind of bookkeeping you want to use?

I experienced a similar issue and this is usually tied to some sort of missing account configuration. You can try these steps:

• Make sure the income account is set for the product. You can do this by checking under the invoicing tab for the selected product. The income account for the product may have already been set for at the Product Category level. Just make sure this is done

• Set Account receivables and Account payable for the customer

• For the journal the invoice is recorded under, set the default debit account and default credit account.

In my own case, I had to set the default credit and debit account for the Customer Invoices journal to resolve the issue.

I had same problem. My solution was to install the Accounting module and to set-up the "Income Account" and "Expense Account" for the product, as well as the accounts for the customer.