when i got my digital hi-8 cam like 4 years ago, it was one of the first firewire cameras.... the firewire cable that came with it, was flakey to say the least... i practically had to tape it in place to get it to stay in the port on the camera.
newer cables work better, so i don't think it was the port per se
my point is just that i'm surprised you'd have a problem with such a recent camera... and canon should also pay for the new cable (in theory). good that it's a relatively simple problem though. enjoy