Open up polls.php.
Find:$vote_cookie = setcookie("voted_".$poll_id, $poll_aid, time() + 30000000, COOKIEPATH);Replace:$vote_cookie = setcookie("voted_".$poll_id, $poll_aid, time() + 86400, COOKIEPATH);
Find: $get_voted_aid = $wpdb->get_var("SELECT pollip_aid FROM $wpdb->pollsip WHERE pollip_qid = $poll_id AND pollip_ip = '".get_ipaddress()."'");Replace: $get_voted_aid = $wpdb->get_var("SELECT pollip_aid FROM $wpdb->pollsip WHERE pollip_qid = $poll_id AND pollip_ip = '".get_ipaddress()."' AND pollip_timestamp <= '".(current_time('timestamp')+86400)."'");
Untested =)