Magento: Fatal error: Call to a member function getModelInstance() on a non-object in app\Mage.php on line 432

Question

I want to call a PHP file using ajax where in that PHP i will place order by the ajax call. But it throws error while i am using app/Mage.php from that file

Answer 1

Your proposed solution is not optimal. You have not initialized Magento so module XML is not loaded yet and the factory pattern does not work.

Simply use either:

Mage::init(); // 1.5+ 

or

Mage::app(); // (pretty much anything) below 1.5

before using getModel.