MarketPress - Headers Sent

Not noticed this before but when posting a new post I get these errors:

Warning: Cannot modify header information - headers already sent by (output started at /public_html/wp-content/plugins/marketpress/marketpress.php:9738) in /wp-includes/class-wp-ajax-response.php on line 129

The only thing I uploaded today but not yet installed is the new password plugin for in posts and didn't see this error yesterday..... I've not looked in the files yet, thought I would mention it.