Hi Jen,
I'm sorry to hear about the trouble you are having. I'm not aware of any technical problems that should prevent you from posting listings as you have described, so I suspect there is just something you will need to do differently to get your listings posted (which we should be able to help you out with).
If you are still in need of assistance with this problem, please contact our customer support team using the web form on the following page: http://www.auctiva.com/help/requesthelp.aspx
-Mike