I'm receiving "Access Restricted" error in my JoomlaPrevious Joomla versions have had a known bug that results in Restricted Access error messages on some pages. The problem has been fixed in the latest Joomla version (currently 1.0.13).
Thus to solve this issue we recommend upgrade to the latest Joomla version. Check this link on how to upgrade Joomla:
http://www.siteground.com/tutorials/joomla/joomla_upgrade.htm
If you have problems with the upgrade you can order Siteground's Development services:
https://www.siteground.com/support/showform.php?subtopic=60