line 115 needs to check if EMAIL_DISCLAIMER is empty, i.e.

Code:
        if (EMAIL_DISCLAIMER != '' && !strstr($email_text, sprintf(EMAIL_DISCLAIMER, STORE_OWNER_EMAIL_ADDRESS)) && $to_email_address != STORE_OWNER_EMAIL_ADDRESS && !defined('EMAIL_DISCLAIMER_NEW_CUSTOMER')) $email_text .= "\n" . sprintf(EMAIL_DISCLAIMER, STORE_OWNER_EMAIL_ADDRESS);
without this you get

[18-Mar-2012 03:20:04] PHP Warning: strstr() [<a href='function.strstr'>function.strstr</a>]: Empty delimiter in /var/www/vhosts/pier1.meyers.com/httpdocs/includes/functions/functions_email.php on line 115