I installed a contribution for OS Commerce called - Cross-Sell (XSell) Module v2.3.
I was able to troubleshoot most of the problems and get the contribution working to a degree. However, I receiver the following error message when I try and UPDATE a product or save a change to a category.
Warning: Cannot modify header information - headers already sent by (output started at /home/gallery5/public_html/catalog/admin/includes/languages/[url removed, login to view]) in /home/gallery5/public_html/catalog/admin/includes/functions/[url removed, login to view] on line 40
I searched the OSC forums and found some reference to whitespace(s) being the problem either before . I have checked this and it does not seem to be the case.
At this point I can't add products to the store or edit products or categories.
I will be happy to provide all necessary passwords, etc to get this Contribution working.