huskyquilter, it is not advisable to use a free motion foot with a ruler; you really should be using a ruler foot for your machine. The ruler foot has a higher edge, making it less likely that the needle will contact the ruler (breaking the needle and possibly flinging needle pieces into your face or throwing your machine out of time).

This happens to me sometimes too. Don't know how, but the thread sometimes gets out of the uptake arm on my machine.