you can use the attached ~~"product_info.php"~~ and replace it with yours (if you don't have changed it befor).
the product_info.php is based on the actual shopversion ~~"oscommerce-2.2rc2a"~~

if you have already a changed version of the product_info.php please follow the instruction.
2 files must be edited:
1.) product_info.php
2.) application_top.php

this version works correctly
based on orig.files of osc
don't use the files befor.
screenshot included