While activating Revolution Slider plugin it is throwing fatal error

Hi, I have purchased Aqua wordpress theme. To activate the Revolution Slider plugin I have imported the zip file that you have provided in Plugin section and installed the plugin. After the installation while I’m activating the slider plugin it is throwing fatal error (I have tried in both localhost and on server).

The error message it is showing is,
Fatal error: Uncaught Error: [] operator not supported for strings in /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-content/plugins/revslider/includes/framework/base-admin.class.php:71 Stack trace: #0 /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-content/plugins/revslider/admin/revslider-admin.class.php(465): RevSliderBaseAdmin::addMetaBox(‘Revolution Slid…’, ”, Array, NULL) #1 /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-content/plugins/revslider/admin/revslider-admin.class.php(72): RevSliderAdmin->addSliderMetaBox() #2 /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-content/plugins/revslider/admin/revslider-admin.class.php(44): RevSliderAdmin->init() #3 /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-content/plugins/revslider/revslider.php(165): RevSliderAdmin->__construct(‘/mnt/data/vhost…’) #4 /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-admin/includes/plugin.php(1897): include(‘/mnt/data/vhost…’) #5 /mnt/data/vhosts/casite-987049.cloud in /mnt/data/vhosts/casite-987049.cloudaccess.net/httpdocs/wp-content/plugins/revslider/includes/framework/base-admin.class.php on line 71