Today I was going crazy because whenever I tried to update customer information from admin it was redirecting me to admin dashboard. It was working perfectly on previous server and on my local. After debugging for a while I couldn't find the solution for the issue at all.
Our client wanted to integrate mailchimp with magento. So I dig for extension and found this awesome free magento extension called mageMonkey. I installed it through magento connect using key: http://connect20.magentocommerce.com/community/Ebizmarts_MageMonkey
In Magento you can load your model with getModel. You can optionally pass parameters to the model class constructor. All you need to do is:
Mage::getModel('model_class', 'arguments_as_array_if_any');
For example: I want to load Data.php model from: https://github.com/dbashyal/Magento-General-Module-Extension