You shouldn't be using a USB connection to get video from a DVD camcorder.
With a DVD camcorder, you first finalize the disc and then put the disc into your computer's disc drive. Then use Add Media/From PC DVD or Camcorder to rip the video from the disc to your computer and into your project.
I have a mac, mini disc cannot go into it
What is the camera model?
As far as I know mac does not play mini disk via the slot drive.
You might need to find someone with a pc that will copy the files from the disk.