All I get is "You do not have permission to access this page."

When i try to create a pop up all I get is this message: "You do not have permission to access this page." / "Du hast nicht die erforderlichen Rechte, um auf diese Seite zuzugreifen."

I'm using wordpress 3.5, Popover plugin 4.4.3 and Xtreme One 1.5.2 - until now I havn't encountered this error.