You have installed using an old version of an installer (one that used to install "into" the sim) AFTER you already installed something else using the current version of the installer (which installs "outside" the sim), that's why you have two Addon Manager menus, and nothing will work.
- Uninstall everything
- Reinstall everything using ONLY the current installers.
- If you have the QW757, install it before anything else, because its installer hasn't been updated.