It may be that the safety sensor "eyes" at the floor level are out of alignment. There should be lights on them that let you know when they are lined up.
Also, it's possible that there is a spot in the track where the door is hitting some resistance and binding slightly. You should be able to adjust the force tension + or - to allow it to handle a little extra resistance.
PS. Is this Erin Hussey in Kelowna?