Problem when going live with application

[eluser]nigelb[/eluser]
which have built an application which performs faultlessly when it is installed on our development server. However when we move it to the clients live web server we are seeing a 404 error page when loading a address in the format...

http://www.domain.com/db/index.php/dropdown/model

any ideas? We have tried playing around with the URL Protocol but didnt get anywhere/