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You are using Image/Adjustments/Replace Color..right?  Here is an article that speaks to your issue. http://planetphotoshop.com/replace-color.html

Seems that this procedure doesn't work with black and white because Photoshop does not recognize black and white as colors. Black or white neither have any hue, which is what that adjustment changes. You can prove this by going to the Adjustment/Hue Saturation command. Move the hue sliders and you will see the colors of blue and red change, but neither the black or white. The only adjustment available for black and white is lightness.

However, there are other ways to do this besides trying to use this command. I would simply select the black or white with the quick selection tool, magic wand or Quickmask, isolate it on a layer (Ctrl/Cmd +J) then you can fill it with a new color, add a color overlay effect, etc. Any number of methods.