Some time in the past couple of weeks all of my product pages have started returning 404 headers instead of 200, which of course is a bad thing. The page comes up and looks perfect to the visitor, so I didn't notice until awstats started showing hundreds of 404 errors each day.

If I turn off the search engine friendly URLs the pages return 200 like they're supposed to. But I prefer the SE URLs because they look cleaner and it was easier to write a robots.txt to block duplicate content than it would have been to add meta robots blocks to any page with a cPath variable. More importantly, the site is several months old and most of the pages are indexed in the big 3 SEs so I don't want to change every URL.

My guess is that it's an Apache issue since I can't find anything in the osCommerce code that would send a 404 header. It's only on pages like /product_info.php/products_id/116 . To confuse me though, I have a Wordpress blog embedded using a blog.php file and /blog.php/post-plug/ works correctly and sends a 200 header.

Any suggestions where to look for a fix? I've posted on the osc boards as well. And I've found a page that mentions this type of issue but only in relation to Apache 2 and my server is running version 1.3.