Hello, A user who wants to log into their registered account on my Wordpress blog, is getting this message/error: "Warning: Cannot modify header information - headers already sent by (output started at /home/bringbac/public_html/index.php:4) in /home/bringbac/public_html/wp-includes/pluggable.php on line 390" I'm not sure why, and it does not show up for me. I am administrator, and I log in fine, but registered users get that message.