qw I have a Janome and I think I may know what your problem is. On the walking foot, on the right hand side (looking at it as it would be on your machine) is a little bar sticking out. When you screw the foot onto the foot bar (whatever that thing is called) you have to make sure that the little lever is sitting on TOP of the screw that holds your needle in. That is what makes the foot go up and down.
Hope this helps.