problem updating to 3.8

Hi. Just tried to update from Enfold 3.4 something to 3.8. I had made sure I had the latest WP upgrade before. Now getting 500 error, entire site and backend “Briefly unavailable for scheduled maintenance. Check back in a minute.” (that was hours ago). Other than going through FTP and completely re-uploading site. any ideas to rectify or at least avoid in future?

thanks. kate

update: just changed error message to:
Warning: include(/home/kthompson1234/public_html/overnight/wp-content/themes/enfold//includes/admin/register-admin-options.php): failed to open stream: No such file or directory in /home/kthompson1234/public_html/overnight/wp-content/themes/enfold/framework/php/class-superobject.php on line 116

Warning: include(): Failed opening ‘/home/kthompson1234/public_html/overnight/wp-content/themes/enfold//includes/admin/register-admin-options.php’ for inclusion (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/kthompson1234/public_html/overnight/wp-content/themes/enfold/framework/php/class-superobject.php on line 116

Warning: Invalid argument supplied for foreach() in /home/kthompson1234/public_html/overnight/wp-content/themes/enfold/framework/php/class-superobject.php on line 140

Warning: require_once(includes/admin/register-portfolio.php): failed to open stream: No such file or directory in /home/kthompson1234/public_html/overnight/wp-content/themes/enfold/functions.php on line 423

Fatal error: require_once(): Failed opening required ‘includes/admin/register-portfolio.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/kthompson1234/public_html/overnight/wp-content/themes/enfold/functions.php on line 423