Javascript to tigger mp3 on rollover not working on iPhone

on a site I just built http://***.buko.net I'm using javascript to trigger an mp3 sound on a rollover. it works fine on a regular computer in a browser. but on the iPhone there is no sound. using both Safari and Chrome.

You can see the rollover works the key looks as if its depressed. One tap seems to trigger the rollover second tap is the click that takes you to the link. the links are on the bottom left.

I was hoping that someone might be able to point me in the right direction.

Buko