This error often occurs with older versions of the plugin, if on the other hand a current PHP version is used. The two do not get along and may result in a completely white website.
Solution: In the plugin folder search for the following file revslider/includes/framework/base-admin.class.php.
Now look for the following code line:
private static $arrMetaBoxes = '';
and replaces it with:
private static $arrMetaBoxes = array();
After that, you should clear the website cache and browser cache once.