wordpress revslider plugin add-ons

I use Slider Revolution on my WordPress website. The plugin works efficiently but I have a problem with add-ons. The page which displays the add-ons list doesn’t display anything. I have installed and activated 2 add-ons, but they are not showing too. On the plugin page, I receive the error below and ThemePunch Server sign is colored yellow (look at the images)

Notice: Trying to get property ‘code’ of non-object in /home/technolomi/public_html/wp-content/plugins/revslider/admin/includes/functions-admin.class.php on line 392