tlelliott77,
Thanks very much. I had put an incorrect file, Order_Info_Check.php, in the path catalog/includes/modules/Order_Info_Check.php
How did I get the incorrect file:-
When I had unzipped the file ,PWA_0.71.zip, there were two Order_Info_Check.php files and didn't unzip with 'folders option' and so got the wrong file in the 'current' folder into which I had unzipped.
After Reading your post I had unzipped with 'folders option in winzip' and put the correct file in the path catalog/includes/modules