Cannot modify header information

I get this message when I move a way from a page that has just had a tag added via Community Tags.

"warning: Cannot modify header information - headers already sent by (output started at /home/xxxxx/public_html/core/modules/community_tags/community_tags.module:424) in /home/xxxxx/public_html/core/includes/common.inc on line 141."

This does not seem to stop the tag from being added but wil of course scare any users.

What do I do to get rid of it?

-- Ade Atobatele