Hi I have made a fresh install of Zencart and the shop appears ok but I am getting the following message in the admin end:

Fatal error: Cannot instantiate non-existent class: messagestack in /homepages/17/d171565386/htdocs/test/store/includes/autoload_func.php on line 79

I have tried to make sure all the files are uploaded ok...

Can anyone suggest what I might have missed??

Thank you