constant contact plugin errors. I need some help

I hope someone can help get me started in the right direction to fix a few problems.
After installing the constant contact plugin I get these 3 errors I don’t know what is causing it. The functions.php code looks like this:

<?php

// Exit if accessed directly
if ( !defined('ABSPATH')) exit;

/**
 *
 * WARNING: Please do not edit this file in any way
 *
 * load the theme function files
 */
require ( get_template_directory() . '/includes/functions.php' );
require ( get_template_directory() . '/includes/theme-options.php' );
require ( get_template_directory() . '/includes/post-custom-meta.php' );
require ( get_template_directory() . '/includes/tha-theme-hooks.php' );
require ( get_template_directory() . '/includes/hooks.php' );
require ( get_template_directory() . '/includes/version.php' );

How do I resolve these errors?

Warning: session_start() [function.session-start]: open(/var/chroot/home/content/58/10589758/tmp/sess_lm16qe9ccvmb5e6u1v0oc3r4e4, O_RDWR) failed: No such file or directory (2) in /home/content/58/10589758/html/wp-content/plugins/constant-contact-api/functions.php on line 5

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at /home/content/58/10589758/html/wp-content/plugins/constant-contact-api/functions.php:5) in /home/content/58/10589758/html/wp-content/plugins/constant-contact-api/functions.php on line 5

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /home/content/58/10589758/html/wp-content/plugins/constant-contact-api/functions.php:5) in /home/content/58/10589758/html/wp-content/plugins/constant-contact-api/functions.php on line 5

THE SITE:
anniesnaturalmedicine.com
The site was designed by someone else previously and I’m trying to add some features like the email sign up form – constant contact.