I am having this same issue.
I go through the event creation process and enter all the ticket information via WP.
When I publish the event, it gives me an error saying no Ticket was created for the event.
I then have to go to Eventbrite and manually create the ticket there, then save then event there.
Once I do that, the ticket information shows up correctly in WP.
But for some reason the ticket information created in WP during the event creation process is not being passed to Eventbrite correctly.
Eventbrite seems to have different options for tickets, too, so maybe they did change something on their end and your API calls might need to be updated?