DarkFire Xomotron

Every time I try to create a store on market place I get denied, and get this message...... Sorry, you do not have sufficient privileges for that action. Please click the Back button on your browser. Why? Do I have to be a premium member to have a store? Thank you for your reply, but I have not even been able to get past clicking on the tab to "create a store". I get the above message. So I am stuck at this time until I figure out what is wrong.