Well, after 18 hours (no joke!) of going round and round in circles, with a little help from the developer of Zen Cart we spotted something: For a script running called phpinf0.php we get _SERVER["PHP_SELF"] /phpinf0.php/phpinf0.php which is clearly wrong and breaks certain scripts. Finally, I ended up right back here! http://forum.nginx.org/read.php?11,212439,212439#msgby talkingnews - Migration from Other Servers
Just to add, I have, of course, put all this detail on the Zen Cart forum, but they've not been able to come up with anything.by talkingnews - Migration from Other Servers
Apologies in advance for the length of this message, I'll try and get all the relevant info in 1 post: The server: Ubuntu 11.10 Nginx 1.0.10 php-fpm 5.3.8 Brand new clean fresh install of Zen Cart 1.3.9h - this is a fork of OsCommerce, which I know works fine on NGINX as there is a Wiki page with the rewrite rules for it. The front end runs like a dream - REALLY fast even on a tiny unby talkingnews - Migration from Other Servers