Apple Mini-DVI to Video Adapter doesn't fit my aluminum iMac

I previously had a 17" white iMac (pre-Intel) machine, and about 6 months ago I bought the mini-DVI to video adapter so I could connect it to my television. Worked like a charm. But I recently bought a new aluminum iMac, and the adaptor doesn't fit into the mini-DVI port in the back of the machine. It appears the adaptor and port are both male ends.

Has the port changed on the aluminum iMacs? The product description for the adaptor on Apple's website says it works with iMac (Intel Core Duo). Isn't the aluminum iMac an Intel Core Duo? I can't figure out why it doesn't fit and which cable I'm supposed to be using instead.

Any advice would be appreciated!