PHP + HOST = 404 Page Not Found

[eluser]Unknown[/eluser]
Good afternoon everyone ..

A developer (freelancer) made ​​a system for the company I work and am trying to set it up in a host.
When run locally (EasyPHP or Xampp) everything runs normally now when sent the files to the host and try to access the domain returns '404 - page not found '

P.S. I've already uploaded the files in three different hosts, always the same error.

I can also pass the username and password if any good soul are interested in taking a deeper look..
I appreciate any help that you guys can give me,

Finishing.. I have no knowledge of php but my research indicates that my problem must be there..
Thank you all.

[eluser]Peham[/eluser]
Do you know that is there any script used by the developer in this project? Is it codeigniter?

[eluser]Unknown[/eluser]
Thanks for reply, and yes... it is Codeigniter... at least I found inside the directory /system/core/ a config archive named Codeigniter.php.....

[eluser]Jan_1[/eluser]
Did you check out the .htaccess-file? You might have to optimize it.