Just read you are using BlackMagics DaVinci.
BlackMagic is an industry leader for high end professional video.
Made their mark with capture cards and editing bays.
Two things, DaVinci is overkill for a novice but more importantly, it does not support FireWire, it won't see your camera.
Use WinDV to pull the footage then you can use DaVinci for editing if you want.
WinDV
What Camera, make and model.
Depending on the answer it may have a proprietary CO/DEC, not uncommon,.
A CO/DEC is a compression / decompression algorithm.
Without the correct CO/DEC your editing software can't decompress the compressed footage because it does not understand the math used to compress.