Hi RadioGuy,
I'm sorry to hear about the trouble you are having, but it sounds like you were informed correctly by our customer support team and misinformed by eBay. If you tried to post a listing through Auctiva and see an API error when you click the red number in the "Notifications" section along the top of your account, it is indicative that eBay rejected the listing and returned that error.
Listings that are posted through third party services such as Auctiva are submitted through eBay's API, which is the system that third party developers use to exchange information with eBay, and listings that are posted directly through eBay are not submitted through eBay's API.
If you are receiving an API error when trying to list the item through eBay and you are able to post the same item through eBay, it is indicative that their is either a restriction on your account preventing you from posting through third party listing services or that there is a bug in the eBay API.
That being said, I don't see any records of posting failures in your account nor am I able to find any support cases on yours in our system. If what I have described does not seem to address what you are experiencing, I recommend contacting our customer support team using the web form on the following page of our site: http://www.auctiva.com/help/requesthelp.aspx
-Mike