Oracle Forms

hi all ,
i am using forms 10g rel2 , win xp sp2 professional .

i am trying to use read_image_file built-in , it never works ,

i have an image whose name is pic with bitmap extension(bmp) , on drive d:\ ,
and an image item whose name is image4 .

i am using it as so ,

read_image_file('d:\pic','bmp','image4') ;

and it never works , could you guide me , please ?

thanks in advance