I launch iDVD (7.0.4), connect my Canon HV20 camcorder (with a FireWire cable), and press the OneStep DVD button. I see the following dialog box:

When I press OK, iDVD goes back to the startup dialog (with no indication of what's wrong):

I've tried inserting the blank disc in advance, but that makes no difference.
I've confirmed (using System Profiler) that the camcorder is connected:

I've tried this on my MacBook Pro running Mac OS X 10.6.4, and a PowerBook running 10.5.8 with the same problem on each.
