Joomla! 1.6.x before 1.6.2 allows remote attackers to obtain sensitive information via an empty Itemid array parameter to index.php, which reveals the installation path in an error message, a different vulnerability than CVE-2011-2488.
https://exchange.xforce.ibmcloud.com/vulnerabilities/68881
http://developer.joomla.org/security/news/341-20110402-core-information-disclosure.html