Is this the first time that you are trying this camera with iMovie?
You may well know this already; if so appologies.
This camcorder can down convert the recorded HDV to DV. Do you know if the camcorder is set to iLink conversion ON or OFF. If the conversion is ON and you have recorded in HDV then the output through the firewire will be DV.If you have recorded in HDV and you want to output in HDV then you have to select ILink conversion to OFF.Also the setting of VCR HDV/DV on your camcorder can affect the ability of iMovie seeing your camcorder.
If you do have to make any changes to the camcorder settings be sure to do them before connecting the firewire cable or iMovie will not recognise these changes.
So...... What format was the camcorder recording in...HDV or DV ?
Is iLINK conversion ON or OFF ?
What is VCR HDV/DV set at..AUTO,DV or HDV?