Nope, the server path is not the problem. Still getting the same PHP error when I try to edit the post after inserting the shortcode.
No I can’t get back into the edit screen for that post but it does load perfectly in the front end – http://gosselin.co.za/2012/03/water-moving/. Had a thought. I think the server path to the magento site causes WordPress to ignore/change it and not load the class. That server path is /usr/www/*****/galeriephoto.co.za – Those dots may be the problem. I’ll get the server guys to change it and come back to you.