error message received

When I put the shortcode into the widget area the optin form appears, but above it I get this message:

Warning: Invalid argument supplied for foreach() in /home/edgamboamd/www/edgamboamd.net/wp-includes/shortcodes.php on line 297

How do I fix this?

http://ww.wp.xz.cn/extend/plugins/feedburner-optin-form/