Warning: simplexml_load_file(): I/O warning : failed to load external entity "/var/www/online/app/etc/local.xml"  in /var/www/online/app/Mage.php on line 767

#0 [internal function]: mageCoreErrorHandler(2, 'simplexml_load_...', '/var/www/online...', 767, Array)
#1 /var/www/online/app/Mage.php(767): simplexml_load_file('/var/www/online...')
#2 /var/www/online/app/code/core/Mage/Core/Model/Config.php(293): Mage::isInstalled(Array)
#3 /var/www/online/app/code/core/Mage/Core/Model/App.php(413): Mage_Core_Model_Config->loadModulesCache()
#4 /var/www/online/app/code/core/Mage/Core/Model/App.php(343): Mage_Core_Model_App->_initModules()
#5 /var/www/online/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#6 /var/www/online/index.php(89): Mage::run('', 'store')
#7 {main}