Icons won't change for some reason In the dock that is
You using CandyBar to change the icons mate? I have had this a few times and what fixed it for me was dragging the application out of the dock and re applying it, I don't know if there is a temporary cache or image file that is created when changing the icons, but after I put the application back in the dock it worked just fine. I think I opened up the terminal and ran the command 'killall Dock' just to make sure.
Hope this helps.