Magento - Error in loading model in Magento Extension?

I am developing a magento extension in which i am trying to insert values to a database table, but the problem i am having is that the model is not loading. The problem is when i am calling `save()` function in my controller then there comes an error on page which is : ``` Fatal error: Call to a member function beginTransaction() on a non-object in /var/www/magento/app/code/core/Mage/Core/Model/Abstract.php on line 313 ``` and when i check for error log in my `system.log` file then i saw this error : ``` Warning: include(Gwb/Magecrmsync/Model/Mysql4/Magecrmsync.php): failed to open stream: No such file or directory in /var/www/magento/lib/Varien/Autoload.php on line 93 ``` I have googled it but couldn't find the answer. Please help Here's my `config.xml` code : ``` <?xml version="1.0"?> <config> <!-- turn on our module, required for install support --> <modules> <Gwb_Magecrmsync> <version>0.1.0</version> </Gwb_Magecrmsync> </modules> <frontend> <routers> <magecrmsync> <use>standard</use> <args> <module>Gwb_Magecrmsync</module> <frontName>magecrmsync</frontName> </args> </magecrmsync> </routers> <layout> <updates> <magecrmsync> <file>adminhtml.xml</file> </magecrmsync> </updates> </layout> </frontend> <admin> <routers> <magecrmsync> <use>admin</use> <args> <module>Gwb_Magecrmsync</module> <frontName>magecrmsync</frontName> </args> </magecrmsync> </routers> </admin> <adminhtml> <menu> <menu1 translate="title" module="magecrmsync"> <title>Synchronize</title> <sort_order>999</sort_order> <children> <menuitem1 module="magecrmsync"> <title>Customers</title> <action>magecrmsync/adminhtml_customers</action> </menuitem1> <menuitem2 module="magecrmsync"> <title>Orders</title> <action>magecrmsync/adminhtml_orders</action> </menuitem2> <menuitem3 module="magecrmsync"> <title>Products</title> <action>magecrmsync/adminhtml_products</action> </menuitem3> <menuitem4 module="magecrmsync"> <title>Settings</title> <action>magecrmsync/adminhtml_settings</action> </menuitem4> </children> </menu1> </menu> <acl> <resources> <admin> <children> <menu1 translate="title" module="magecrmsync"> <title>Synchronize</title> <sort_order>999</sort_order> <children> <menuitem1> <title>Customers</title> </menuitem1> <menuitem2> <title>Orders</title> </menuitem2> <menuitem3> <title>Products</title> </menuitem3> <menuitem4> <title>Settings</title> </menuitem4> </children> </menu1> </children> </admin> </resources> </acl> </adminhtml> <global> <!-- turn on models --> <models> <magecrmsync> <class>Gwb_Magecrmsync_Model</class> <resourceModel>Magecrmsync_mysql4</resourceModel> </magecrmsync> <Magecrmsync_mysql4> <class>Gwb_Magecrmsync_Model_Mysql4</class> <entities> <magecrmsync> <table>magecrmsync</table> </magecrmsync> </entities> </Magecrmsync_mysql4> </models> <!-- turn on models --> <!-- turn on database connections --> <resources> <!-- setup is needed for automatic installation --> <magecrmsync_setup> <setup> <module>Gwb_Magecrmsync</module> </setup> <connection> <use>core_setup</use> </connection> </magecrmsync_setup> <magecrmsync_write> <connection> <use>core_write</use> </connection> </magecrmsync_write> <magecrmsync_read> <connection> <use>core_read</use> </connection> </magecrmsync_read> </resources> <blocks> <magecrmsync> <class>Gwb_Magecrmsync_Block</class> </magecrmsync> </blocks> <helpers> <magecrmsync> <class>Gwb_Magecrmsync_Helper</class> </magecrmsync> </helpers> <layout> <magecrmsync> <file>adminhtml.xml</file> </magecrmsync> </layout> </global> </config> ``` Here's my function in my controller file : ``` public function settingsAction() { if($this->getRequest()->getPost()) { try { $login_info = Mage::getModel('magecrmsync/magecrmsync'); $username = $this->getRequest()->getPost('username'); $password = $this->getRequest()->getPost('password'); $login_info->setUsername($username); $login_info->setPassword(md5($password)); $login_info->save(); Mage::getSingleton('adminhtml/session')->addSuccess("Login Information has been updated successfully."); } catch(Exception $e) { Mage::getSingleton('adminhtml/session')->addError($e->getMessage()); } } else { Mage::getSingleton('adminhtml/session')->addError("Error! Please try again."); } $this->_redirect('/*/*'); } ``` Can anyone identify the problem here which is not letting my model to load? Any help would be appreciated and will be helpful to me. Thanks in advance