The audio data is likely mixed in with the video data ... FCP does not like that and you'll need "demux" the clip. You can use the free
MPEG Streamclip to convert your video to a more FCP edit friendly format eg Export to Quicktime (.mov) using DV as the compressor.
Certified, good grief man, spoken like a true elitist ... welcome to the club 😉
Of course, you can also use Compressor and a quick cluster for this.
If you have a bunch of files, it's pretty simple to set up a batch to convert muxed .dv to Quicktime DV transcodes. The setting is found in the Advanced Format Conversion > Standard Definition presets.