The SONY DCR PC100 DV cancoder can't be recogized by PowerBook(firewire), G4 Cube, iMac DV and Power Mac G4/400. But the Power Mac G4 dual processor can see it. These machines all run Mac OS 9.0.4, firewire v2.5 and iMovie 2.
Is there anyone has same experience ?

I've had no problems with my Nov 1999 DCR-PC100 and B&W G3/400 (MacOS 9.0.4) using Final Cut Pro or iMovie 1/2. Even the MStick reader works with VirtualPC 2.x and a USB/din9 serial adaptor.

I use my DCR PC100 camcorder all the time with my PowerBook 400 Firewire and my G4/450 with iMovie without any problems.

Make sure it's in VTR mode and that it's got power. Other than making sure you have all the firewire extensions installed I'm not sure what else you could check.

Good luck!