Header errors.

Hello there, there is a problem with my wordpress site. When i go to to it a white screen with text that says

“Warning: Cannot modify header information – headers already sent by (output started at ……/public_html/mjduniverse.com/main/wp-includes/functions.php:1) in ……./public_html/mjduniverse.com/main/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 91

Warning: Cannot modify header information – headers already sent by (output started at ……./public_html/mjduniverse.com/main/wp-includes/functions.php:1) in ……/public_html/mjduniverse.com/main/wp-includes/pluggable.php on line 896