Hi sscrabble,
Thanks for posting about this behavior here. I reviewed your account and found that, when we submitted your recent listings to eBay on your behalf, eBay's system rejected them and returned the API error message you quoted indicating that you must accept eBay's international selling agreement before the listings can be posted.
As the error message indicates, all you should need to do in order to be able to post these listings successfully is use the link provided in the API error message to accept eBay's new international selling agreement.
Once you have accepted the new international selling agreement, you should then be able to post these listings to eBay successfully by trying again.
I am not quite sure why you have not been able to get to the new agreement using the link provided in the API error though. I just clicked the link in your post above and was taken to the correct eBay page so you should be able to do the same.
I hope this helps. If you need any further assistance with your account, please feel free to contact our customer support team by mousing over the “Help” tab within your account and selecting the “ File Support Case” option.
-Mike