I'm attempting to override the core navigation module in Magento with my plugin however, it is not working as it should. The plugin runs however an error is thrown.

2015-01-19T06:43:13+00:00 ERR (3): 
exception 'Mage_Core_Exception' with message 'Invalid block type: VNav_Catalog_Block_Navigation' in C:\wamp\www\magento\app\Mage.php:595
Stack trace:
#0 C:\wamp\www\magento\includes\src\__default.php(28016): Mage::throwException('Invalid block t...')
#1 C:\wamp\www\magento\includes\src\__default.php(27958): Mage_Core_Model_Layout->_getBlockInstance('catalog/navigat...', Array)
#2 C:\wamp\www\magento\includes\src\__default.php(27993): Mage_Core_Model_Layout->createBlock('catalog/navigat...', 'catalog.leftnav')
#3 C:\wamp\www\magento\includes\src\__default.php(27760): Mage_Core_Model_Layout->addBlock('catalog/navigat...', 'catalog.leftnav')
#4 C:\wamp\www\magento\includes\src\__default.php(27726): Mage_Core_Model_Layout->_generateBlock(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#5 C:\wamp\www\magento\includes\src\__default.php(27731): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#6 C:\wamp\www\magento\includes\src\__default.php(13941): Mage_Core_Model_Layout->generateBlocks()
#7 C:\wamp\www\magento\app\code\core\Mage\Catalog\controllers\CategoryController.php(148): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#8 C:\wamp\www\magento\includes\src\__default.php(14015): Mage_Catalog_CategoryController->viewAction()
#9 C:\wamp\www\magento\includes\src\__default.php(18399): Mage_Core_Controller_Varien_Action->dispatch('view')
#10 C:\wamp\www\magento\includes\src\__default.php(17933): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#11 C:\wamp\www\magento\includes\src\__default.php(20705): Mage_Core_Controller_Varien_Front->dispatch()
#12 C:\wamp\www\magento\app\Mage.php(684): Mage_Core_Model_App->run(Array)
#13 C:\wamp\www\magento\index.php(85): Mage::run('', 'store')
#14 {main}

Plugins files:

C:\wamp\www\magento\app\code\local\VNav\Catalog\etc\config.xml

<?xml version="1.0"?>
<config>
<modules>
    <VNav_Catalog>
        <version>0.1.0</version>
    </VNav_Catalog>
</modules>

<global>
    <blocks>
        <catalog>
            <rewrite>
                <navigation>VNav_Catalog_Block_Navigation</navigation>
            </rewrite>
        </catalog>
    </blocks>
</global>
</config>

C:\wamp\www\magento\app\code\local\VNav\Catalog\Block\Navigation.php:

class VNav_Catalog_Block_Navigation extends Mage_Catalog_Block_Navigation{}

C:\wamp\www\magento\app\etc\modules\VNav_Catalog.xml:

<?xml version="1.0"?>
<config>
<modules>
    <VNav_Catalog>
        <active>true</active>
        <codePool>local</codePool>
        <depends />
    </VNav_Catalog>
</modules>
</config>

Any ideas why? Thanks!