I used a program called MigrateMe to upgrade a site to 4.0. Apparently Joomla51 uses MooTools in their templates Javascript library and J.4 does not include MooTools. I need a solution to this issue. As I soon as I installed the 4.0 template I got a 500 error BEHAVIOR::CAPTION NOT FOUND - it seems the Moo Tools in 3.0 templates hangs around