unexpected 404

[eluser]umbongo[/eluser]
I loaded a new M,V,C into my CI application, however, when i try to load example.com/newcontroller i get a 404. All other controllers work. Any ideas what I have missed??

Secondly, when it is 'working' if i append anything onto the end of a URL i need to go to example.com/controller/controller[/whatever]. going to example.com/controller[/whatever] gives a 404. example.com/controller works. What have i set up wrong???