"Found a solution for Now" I have a Panasonic HDC-HS900 camcorder and I could not get the hard drive to mount on the desktop like before after upgrading to Lion. Just upgraded a few weeks ago and have not tried to import movies until today. Here is what I did to get the HDD to mount on the desktop.
1. Camcorder on and NO programs open (iMovie or Aperture) or you can have iMove open.
2. Plug in USB cord to the camcorder.
3. Choose "Recorder" NOT "PC"
4. Select Media - "HDD"
5. "CAM - HDD" - should now have mounted on your Mac desktop.
6. Open iMovie.
7. Click "Open camera import window".
8. iMovie now detects your Panasonic Camcorder and you can import your movie clips like before.
If you have iMovie open it will auto detect your Panasonic Camcorder after you select HDD (step 4) and you can skip steps (6 & 7) then import your movie clips like before.
When finished I goto the desktop and eject the "CAM-HDD" then unplug the USB cable from the camcorder.
Camcorder returns to normal operation without locking up.
Hope this helps everyone.
Dave