I am having a little trouble understanding what exactly you are trying to do.  I do understand that you are using a Panasonic AG-DVX100p camera which is mini dv tape.  Are you trying to import directly from the camera?  If so, MEP will not see the contents of the tape as a file, even if it recognized the camera.  You could use the camera as an input source and capture the video from the camera.  To do this, connect your camera to the PC using your DV Out connector IEEE1394 (sometimes called firewire), press the "record" button on MEPs video monitor and a menu will come up where you can select the camera as the input source and record the contents of the tape to a digital file.

If you have already transferred the contents of the tape to a computer and are trying to import the video file to MEP, you need to make sure that the file format is one that MEP will accept such as AVI, DV-AVI, MPEG-1, MPEG-2, MPEG-4, etc.

Feel free to add more information about what you are trying to do and I would be happy to better help you out.