URGENT: Site down after failed theme update

Hi Guys, we just tried to upgrade to the latest theme version and for some reason it got stuck, we now have the site down and this error

Warning: require_once(framework/avia_framework.php) [function.require-once]: failed to open stream: No such file or directory in /home/challeng/public_html/wp-content/themes/enfold/functions.php on line 77

Fatal error: require_once() [function.require]: Failed opening required ‘framework/avia_framework.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/challeng/public_html/wp-content/themes/enfold/functions.php on line 77

Any ideas what we can do to fix this and get it back to how it was without losing any data, settings etc?

Many Thanks