Magento 1.9.1 Order Conformation mail are not send.

Quick solution is:

Go to the following location: /app/code/core/Mage/Core/Model/Email/Template.php

Change Line 407

if ($this->hasQueue() && $this->getQueue() instanceof Mage_Core_Model_Email_Queue) {

to

if (!($this->hasQueue() && $this->getQueue() instanceof Mage_Core_Model_Email_Queue)) {

Also this extension helps you to manage cron jobs in Magento: <a rel="nofollow" href="http://www.magentocommerce.com/magento-connect/aoe-scheduler.html">AOE Scheduler</a>

Hope this help...