Error in F-28

Hi Experts,

In transaction F-28 when I click on Process open items appears the following message:

No open items were found

Message no. F5170

I think it is related with an error I had when creating the invoice in VF04, when I save it appears the following message:

Document 90000032 saved (error in account determination)

Message no. VF051

I´ve been looking but still I can´t solve this. If you need it you can check the screen shot after doing "environment--> Acc.determ.analysis --> Revenue Accounts"