Problem With Installing to Safari

[spedonti 0]

    I have downloaded both Evernote and Evernote Web Clipper for Safari, but I have only been able to successfully install Evernote and not the Web Clipper. When click on the file in my downloads, called,"evernote-web-clipper-latest.safari.extz," the pop up shown in the image from below shows up, despite having enabled the extension, or so I think.

   Can anyone help me figure out my problem? Thanks.