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?

[eluser]antoniog[/eluser]
Addition.
Entering the path of the image instead of base_url ("images / logo.jpg") the image is not exposed, while the address bar by typing http://example.com/igniter/images/logo.jpg, the 'image is displayed.
Browser used: Firefox 11.

[eluser]antoniog[/eluser]
CSS diplayed!
CSS displayed by paste the sheet code with style tags.

[eluser]InsiteFX[/eluser]
And where did you place your image directory?

You need to show your directory structure!

[eluser]CroNiX[/eluser]
Also, what is your base_url set to?

[eluser]Matalina[/eluser]
I think spaces will also cause issues.

Code:

base_url (“images/logo.jpg”)

[eluser]CodeIgniteMe[/eluser]
Can you inspect/view source what the base_url("images/logo.png") generates?

[eluser]antoniog[/eluser]
Solved!
The helper, in particular, "url", were not specified in autoload.php.
I was misled by the manual I'm reading that does not specify who was to set helpers to use in that file.
Thanks to all of you who have tried to give me a real help.