You are attemting to update from your child theme. This path: wp-content/themes/tower-child/plugins/js_composer.zip does not exist! The included plugins are all located in the parent theme plugins folder.
So for this update process to be successful the path should be: wp-content/themes/tower/plugins/js_composer.zip
Just switch to parent theme before trying to update included plugins. Update them and then activate back your child theme.
