Hi scg412,
Thanks for contributing to our forum. The API error message that was returned by eBay when you attempted to post this item seems to suggest that you did not choose the corresponding product from eBay's catalog using the “Find Product” tool on our lister page. However, given that you had already selected the appropriate product using the “Find Product” option, it is currently unclear why this error may have been returned.
I see that you filed a support case about this issue and that it has been forwarded to our technical team for further investigation, so we will follow up with you through that support case as soon as any additional information becomes available.
I also see that you have since been able to post the item successfully, but I do not believe we made any changes on our end between when the errors occurred and when you posted the item successfully that would explain the change in behavior.
In any event, we apologize for any inconveniences this may have caused you and we hope to find out more about the cause of the errors soon.
-Mike