I've done this a few times, and I notice one thing that can really cause problems in any video-editing application: the analog-to-DV conversion hardware. If you get one of the lower-quality (i.e. less expensive) ones, the video will often cause problems with iMovie, iDVD, Toast, Final Cut Express, Final Cut Pro, or any other program you try to use (because it's giving bad digital data).
My dad purchased a $160 Firewire converter that is no longer on the market (the Dazzle Hollywood Firewire box), and, while it did get some video from VHS, Hi8, and other analog inputs, the video often locked up the applications (iMovie 4 and Final Cut Express) that he used to edit the video when he tried to edit certain parts or export it. He still has problems when burning DVDs sometimes, but he's had to have many hassles to get the box working right.
You might want to look into getting a Canopus DV converter, as they are usually very high quality. There are a few other companies that make pretty good DV converters, but I would usually recommend Canopus. Pyro's products are also worth a glance.
However, the DV box might not be the problem. You could also see if iDVD's 'OneStep DVD' feature (where it records a whole tape, then makes a DVD) works. If this does, the problem may reside in iMovie. But I still think it may be the converter's fault; if not that, then you might have a low-quality VCR or old videocamera which is sending a low-quality signal to the converter. Many of the problems my dad had were related to the converter's ability to send proper DV timecode to the computer.
Last update: 03:51 PM Friday, June 30, 2006