Cant get access wp/ White screen

Hi I cant get access to control panel. I get this warning. What to do?? Warning: Cannot modify header information - headers already sent by (output started at /customers/5/5/a/allingaabro-portalen.dk/httpd.www/wp-content/themes/catch-base-pro/inc/catchbase-core.php:1) in /customers/5/5/a/allingaabro-portalen.dk/httpd.www/wp-login.php on line 390 Warning: Cannot modify header information - headers already sent by (output started at /customers/5/5/a/allingaabro-portalen.dk/httpd.www/wp-content/themes/catch-base-pro/inc/catchbase-core.php:1) in /customers/5/5/a/allingaabro-portalen.dk/httpd.www/wp-login.php on line 403