HD dock compatible with Imac?

[ddallas07]

I recently got my adapter for the MiniDisplayport on the back of my Imac so I can hook up my droid RAZR via the HD Desktop Dock I received when I purchased the phone! I know the HDMI works because I can hook my RAZR up to my TV no problem. There is no HDMI port on the back of my Imac so I just got an adapter. Problem is, when I hook it into my Dock there is no recognition of it being connected to the computer. Nothing comes up, no webtop or mirror dock selections, it just sits there idol. Also when I hook my RAZR directly HDMI to the computer it doesn't work. Can anyone help me out, what am I doing wrong?