OK Ron, Julian,
I can see where I went wrong.
There are two 2.1 xertetoolkits on your download page. One of which contains only the changes since November 4, 2013 and the other one, which has all the files (including the styles folder) that was missing from my previous upgrade.
I’ve subsequently downloaded the full 2.1 version and followed the upgrade instructions which worked.
There was one issue with the upgrade: The upgrade inadvertently changed the player engine of previously developed learning objects from the HTML5 player to the Flash player. Therefore, if you had created learning object in xerte2.0 using the HTML5 player, you would have to reset the player after the upgrade to 2.1 (Screen-shot attached).
Regards, Garry