PHP version 5.5, both mbstring and dom are installed on the server.

full error: Call to undefined function LayerSlider\PHPQuery\mb_ereg_match() in /home/arbd/public_html/beta/wp-content/themes/enfold/config-layerslider/LayerSlider/helpers/phpQuery.php on line 1839

I found the issue, mb regex module was disabled on my server. All set now so you can close this ticket.

no errors now, but v6 is whole new animal to learn! I like what I see though, seems much more powerful.