"Add New Category" and add product tag not working


This regards functions generated by the plugin TT Marketpress Frontend Admin. At https://www.wheelofcommerce.com/testaccount12/store-admin/ you can see, on the right side of the page, a button that named Add New Category, and another one to add tags, neither of them work (testaccount12, at the URL, is the username I'm using as example). The first displays a message saying "You don't have permission to do perform this action" when it's pressed, and the second simply doesn't add any tag after being pressed. What's curious is that you can add new categories at the separate page to add new categories to your store here: https://www.wheelofcommerce.com/testaccount12/store-admin/?mpfe_page=product_category, and new tags at https://www.wheelofcommerce.com/testaccount12/store-admin/?mpfe_page=product_tag. How do I fix this?