YES - the cable is broken. The Sony cable works just fine - 2 no-name cables didn't work at all.
Others confirm the same problem:
From [bziggy@telstra.com]
> Hi Morten:
>
> Just wanted to say thanks for your reply.
>
> Your advice was GREAT!
>
> I bought a Belkin Firewire Cable and it works perfectly.
> So the problem was with 2 different low quality firewire cables.
>
> Thanks!
>
> Ziggy.
>