I believe your having issues because the granting of access privileges was not successful. When you bring up the program a key ay the bottom of the page on the left side should say "Priv Access". I have some information here :
http://zimpro.co/blog/zetsy-installation-and-troubleshooting/. My guess is that you have listings with multiple variations. Zetsy CAN handle this but it needs the private access to do so. You can redo this access by using the menu item Tools followed by Grant Private access.
This access is only between the program on your computer and Etsy. I have no access to this info - good from a security aspect, bad from a troubleshooting aspect.