When you finished free motion quilting did you put the feed dogs back up? (I tend to for get that.) That could cause all the mentioned problems. Sometimes mine don't go completely up when I first depress the button, so push it in and out a couple times.
If your feed dogs were up as they need to be for regular stitching, did you have the little lever arm thingy over the needle screw on your walking foot (which causes the foot to work correctly).
Also, re-thread your machine and make absolutely sure your bobbin is in the bobbin case correctly.
Once more thing, turn your machine off and back on (like rebooting your computer) and see if that helps.
If your feed dogs are up and your walking foot is installed correctly, then a call to the dealer might be appropriate.