I had this problem as well when I downloaded this theme for the first time but your solution fixed it.
[07-Jan-2015 08:46:55 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/****/public_html/****/wp-content/themes/cv-card/admin/options-init.php:541) in /home/****/public_html/****/wp-includes/option.php on line 748
