I have the Sport track color. And had the same problem. I bought the junkie cables also. Mine works but I have to plug it in 2 or 3 times to make the drivers pick up.
The Magellan communicator will not help you. I have to use: ExpertGPS to send info to my unit. But will only work when you get the cable working. And the settings right.When cable is plugged in try this:
Start menu,My computer, then right click in field and select properties. Under Hardware tab select Device manager.
In the Device manager go down to ports and open tree. You should see you cable(not GPS) listed as Com2 or Com3. If not you need to check your drivers from Cd again. Try plugging in in and out a couple times.
It is a pain to get everything working but once you get it, it is nice just to click button and install.