1. No GPL or compatible license info.
2. Can anyone have a look at line 53 in social-slider.php?
$ssp64 = dirname(dirname(dirname(__FILE__)))."/".$socialslider."/license.key";
It looks like wp.org is used to host a commercial version of the plugin.
Similar issues reported at http://wordpress.org/support/topic/plugin-social-slider-gpl-issue?replies=3