There seems to be a bug in the new Magento 1.9.1.1
Found this in /var/log/system.log
2015-06-17T15:11:29+00:00 ERR (3): Warning: SimpleXMLElement::xpath(): xmlXPathEval: evaluation failed in app/code/core/Mage/Paypal/Model/Observer.php on line 132
The XPath causing the issue is
$paymentsConfigs = $paymentGroups->xpath('paypal_payments/*/backend_config/' . $countryCode);
Can anyone see an obvious problem here?