font-lock-add-keywords is not being honored

[Rami A]

I have the following color settings in my dotemacs file:

(defconst lconfig-font-lock-faces  
  (list 
   '(font-lock-builtin-face 
     ((((class color)) (:foreground "Red"  :bold t)))) 

   '(font-lock-constant-face
     ((((class color)) (:foreground "Black"     :bold t)))) 

   '(font-lock-preprocessor-face
     ((((class color)) (:foreground "DarkBlue"  :bold t))))

   )
  )

Then I am configuring specific words to be colored in this form:

(font-lock-add-keywords
 'c-mode
 '(
   ("^#[ \t]*\\(ifdef\\|else\\|ifndef\\|if !?defined\\|elif 
!?defined\\|if\\|elif\\|endif\\|ident\\).*$" 1 font-lock-constant-face) 
;#defines 
   )
 )


Unfortunately, in c files # preprocessors stay in blue color and not black as I 
configured "font-lock-constant-face".

Commenting out the lines:

   '(font-lock-preprocessor-face
     ((((class color)) (:foreground "DarkBlue"  :bold t))))

will make them in Red color.
And commenting the lines:

   '(font-lock-builtin-face 
     ((((class color)) (:foreground "Red"  :bold t)))) 


Will bring them back to the violent color that you get when you start emacs 
without a dotemacs file.

What am I doing wrong?