base_url() not expose image and CSS

[eluser]antoniog[/eluser]
Good afternoon everyone.
I am having a problem with the base_url() function.
I made ​​a header which should show precisely through base_url, an image of the logo and style formatting of the page with an external CSS file.
If I run the header file without using base_url everything works fine but not for CodeIgniter work.
The version installed on my server is 2.1.0 and I'm working on a site already exists and the inside of the folder igniter.

Code:

images folder: http://example.com/igniter/images
css folder: http://example.com/igniter/css

This may be a bug?