Missing Firewire Bus

I just bought a new external hard drive (an Iomega UltaMax). I connected it to my (year old) iMac via Firewire 400 but it didn't mount using either Firewire port on the back of my iMac. I then connected it via USB and it mounted fine.

When I check the System Profiler, the Firewire Bus status screen is completely blank (suggesting that there isn't one)!

I called AppleCare and after 40 minutes they suggested that I take it to my local Apple store for testing. Could it be that my Firewire ports aren't activated?!

Not activated, not installed, firewire chip blown many reasons.

Do as suggested and advise the reseller you are there on the recommendation of Applecare and ticket number if you were advised of one.