Using Motion Bro in After Effects cc.2014, I can not install the .list file

Check your version of After Effects: Help > About After Effects…
If you are using 2014.0, then you need to update your version of After Effects, because the Adobe developers have fixed many errors related to the work of extensions. This can be done using the Adobe Creative Cloud application.
For the correct operation of the extension, you need version 2014.2 or higher.