Hi, ohh but this is actually not a fatal error.
When you will go to the third step in the Ad posting, you have only bank transfer method, it will load after a second with prefilled data, then you need to click “Place Order” button.
If the user posting an Ad will not do that the Advert will show in wp-admin / Classifieds panel with “Abandoned” status, which means the user posted an Ad but in the third step did not click place order button, so the payment object was not created.
Sometimes this status can mean that user is still filling the bank transfer form, but in most cases it means user posted an Ad but closed a browser window before clicking “Place Order”.