My b2evolution Version: Not Entered

Howdy,

When blog readers attempt to post a comment, they get the following message (5 times, actually): "Warning: Cannot modify header information - headers already sent by (output started at /home/michae02/public_html/blog/conf/_config.php:3) in /home/michae02/public_html/blog/htsrv/comment_post.php on line 218"

Anyone have a theory or approach for me?

Thanks very much!