If you try to login to the administration of Joomla and you get the error: Invalid Session
try the following fix:go here its a known bug of Joomla , you will have to download the “fix.zip” file attached to the article (you have to be logged in to do that), and replace the files in your Joomla installation.
Where is the attached file?
Hello,
it seems the original article (back in 2007) at joomla forums doesn’t exist anymore (maybe its deleted or moved).
I suggest you to go to http://forum.joomla.org/ and search for a possible solution.