It's hard to say what might be going wrong with Premiere 4.2.1. That version predates DV, so while it should work, it was never designed for that purpose.
I'd recommend getting BTV Pro from
Ben Software. This $40 shareware package does a great job of capturing video via FireWire and a converter box like the Dazzle Hollywood Bridge.
Whatever capture program you're using, make sure the Dazzle is in the right mode (analog in). You can also verify that your Mac sees the Dazzle by checking the Apple System Profiler "Devices and Volumes" tab. You should see the Dazzle connected to your FireWire bus, although it may be labeled as an "audio device".
Bob Currier
Synthetic Aperture