Theme update crashed site

After updating from Fruitful 3.3 to 3.3.1, the following error appeared:

Warning: require_once(/home/[mysite]/wp-content/themes/fruitful/header.php): failed to open stream: Permission denied in /home/[mysite]/wp-includes/template.php on line 572.

Fatal error: require_once(): Failed opening required …./wp-content/themes/fruitful/header.php (include_path=’.:/usr/local/php5/lib/pear’) in /home/[mysite]/wp-includes/template.php on line 572

… Any advice? Is this a permissions issue, or a php issue with the server? Let me know how I can help you troubleshoot. Thanks.