It looks like your camera is supported (see
the libgphoto2 support list - libgphoto2 is what gtkam uses). You could try using gphoto2 directly. It's a command-line interface to all the cameras it supports, and in my experience is more stable than gtkam. They have pretty good
documentation.
If you are using USB, make sure USB support is working - the manual has a
section on doing that.