Hi Matt
Really sorry for the hassle, the next version of Page Builder which should be out this week will resolve it. The issue has arise in the way we’re bundling Page Builder layouts. If your server doesn’t have the fileinfo extension in PHP activated, it hits an issue. The new version of Page Builder will use another method to bundle layouts.
Please go to Appearance > Editor > inc > siteorigin-panels.php
and carefully remove this function:
https://github.com/purothemes/polestar/blob/master/inc/siteorigin-panels.php#L11-L18
Please, let me know how that goes, thanks.