I tried to install membership 2 pro via the dashboard

I tried to install membership 2 pro via the dashboard and it shows the website http://www.samustang.com to install to, but then I get an install error that says The page doesn't have the proper permissions. I then tried it from the dashboard and received the following error: Destination folder already exists. /hermes/waloraweb046/b2122/blu.bdweb309450/wp-content/plugins/membership. The end goal is i have my current website running membership premium 3.5.1.5 and I want to get membership 2 pro. It looks like another administrator has two versions of premium installed, but only one is active. Please let me know what you need from me to get this installed.