I had this same problem. Mike from AUCTIVA sent the following instructions to me and it did the trick. The only down fall is until they get the "PAID" program up and running for imported items, you will have to do this manually;
*Copied directly from the e-mail sent to me from (Auctiva Mike D.)
Sorry about the confusion. The "Mark as Paid" button is currently only used to update the payment status's of Auctiva checkout items for which the buyer indicated he/she would be sending a check or money order.
To update the payment status of items that did not go through Auctiva Checkout, please click the "Transactions" link under the "Sales" tab within your account. Then, next to each item, click the "Add Insurance" button, followed by the "Update" button on the ensuing page.
In the future, we will have a service running that automatically updates this information on a continuous basis but that development is most likely several months off.