Re: Hooking up a Cintiq 12wx to an IMAC?...Help
It sounds like you might be using the wrong adaptor. I use a cintiq 12wx on a macbook and I use the $19 "apple mini-dvi to dvi adapter." I would post a link to it in apple's store, but apparently I have to make a couple of posts here before I can make outside links. Just copy and paste what I put in quotes into a google search and you'll find it.
This one simply adapts the serial dvi cord from the cintiq to my macbook's mini displayport. The usb cord is completely separate, and nothing special.
I'm not certain that the $99 dual link adaptor you have is the issue or that it wouldn't work, I'm just saying that on a macbook I don't use it and my set up works fine.