motion jpeg sounds like a mpeg video file to me but could be wrong, sometimes it can be a vob or dat(weird cameras around) and to watch it properly in other device, not the pc you could need to convert the videos, many apps exist for this task
can you see the contents of the camera when you connect it to the pc?
if that is the case just copy and paste the files
some cameras can be set to use the usb port in 3 different ways, as a camera, print bridge and usb mass storage device
if your camera cannot be recognized as a usb mass storage device and you need digikam to see the files, digikam should let you copy the files you need