Hi,
The way we figured-out the Insurance problem on the USPS International was revising and revising and revising an active listing until we hit upon the cause of the conflict.
You might try revising an active listing to see what it will accept to get the International postage to show. Sometimes, eBay's editor gives a reason that's not obvious on Auctiva's editor (or caught with ERROR CHECK).
Also, it's possible Auctiva's editor might now give a cause. You could try editing an old Saved Listing and see if ERROR CHECK has anything to say on the problem.
I would also suggest you enter a Support Case, so the Auctiva folks have an alert on the problem.
Danno