since the files are the same on the live and testing server, i would suspect something in the database as the cause of the problem on the testing server.
A category name, or a product description or something along those lines.
you can try exporting the data from the live MySQL database then importing it to the local testing database. when exporting an importing, use only the tables that have names beginning with ps4_
if you dont want to export / import, you can dump the data from those tables to get back to square 1.