When trying to install layerslider I only get a 403 Forbidden error page?

When trying to install layerslider I only get a 403 Forbidden error page? http://passitforward.com/wp-admin/themes.php?page=install-required-plugins&plugin=LayerSlider&plugin_name=Layer+slider&plugin_source=http%3A%2F%2Fskywarriorthemes.com%2Fplugins%2Flayerslider.zip&tgmpa-install=install-plugin&_wpnonce=6d8c324a51 How can I install this plugin that was supposed to be FREE with purchase of Fundingpress?!?!?.