Magento Warning: simplexml_load_string() Parser Error

Sometimes when you enable caching in magento, you will get this error:

Warning: simplexml_load_string(): Entity: line 83: parser error : StartTag: invalid element name  in /home/magento/enterprise/lib/Varien/Simplexml/Config.php on line 383

#0 [internal function]: mageCoreErrorHandler(2, 'simplexml_load_...', '/home/magento/enterprise/...', 383, Array)
#1 /home/magento/enterprise/lib/Varien/Simplexml/Config.php(383): simplexml_load_string('loadCache()
#3 /home/magento/enterprise/app/code/core/Mage/Core/Model/App.php(424): Mage_Core_Model_Config->loadModulesCache()
#4 /home/magento/enterprise/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Model_App->_initModules()
#5 /home/magento/enterprise/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#6 /home/magento/enterprise/index.php(86): Mage::run('', 'store')
#7 {main}

I am sure you have custom theme (or extensions) installed, and you can't trust them 100%.

To quickly fix check if you can find any entries when you run:

SELECT * FROM `core_config_data` where path > 0;

If you can, then awesome, you can fix it by running:

DELETE FROM `core_config_data` where path > 0;

Flush your cache and you are good to enable cache again.

If those entries re-appear you need to investigate every single third party additions.

magento get current url

This is how you get current magento page url.

Mage::helper('core/url')->getCurrentUrl();

Source: http://dltr.org/blog/magento/420/Magento-get-current-url-of-a-page.