No Success Message

I have used Constant Contact plugin version 2.4.1.
I have used short-code [constantcontactapi formid=”1″ lists=”31″] to show the form on my page.
It shows perfectly on my page but it doesn’t show any success message for this i have added bellow code to my theme’s functions.php file.

add_filter(‘constant_contact_form_success’, ‘custom_constant_contact_success_message’);
function custom_constant_contact_success_message($success = ”) {
return ‘<h3>My custom HTML here.</h3>’;
}

It’s not working for me.I also get an error msg in wp-admin Constant Contact->Campaigns: Warning: Invalid argument supplied for foreach() in /home/donna/public_html/wp-content/plugins/constant-contact-api/admin/campaigns.php on line 151

Can anyone help?

http://ww.wp.xz.cn/extend/plugins/constant-contact-api/