title: Magento Checkout Redirecting to Cart page
body: <p>When i try to do purchase by clicking place order button in magento,it redirects from checkout page to cart page.This happens only when I select paypal website payments pro as payment method.Paypal express checkout works fine.Magento does not show error in system.log or in exception.log</p>
  
  <p>Magento version - 1.5.1.0.</p>
  
  <p>Could anyone help?</p>