Try turning the iPod all the way up.
I use the same type of connector for mine, and I have no problems.
Try plugging it in to a different input and see what happens.
If that doesnt work, you might want to try a new connector.
I wouldnt bother with the "iPod specific" ones, they are essentially the same thing.
I have an AR connector for my home use (via iPod dock), but just bought a cheap one from Radio Shack that I carry in my truck for when I go to friends houses and take over "music responsibilities".
I'm thinking you just got a bum cable.

LIFE IS SHORT.
DON'T BE A DICK.