The advice from NJ Quilter makes sense but also check to be REALLY sure you are threading your bobbin correctly. The Viking logo should be on top when the bobbin is seated in the bobbin assembly. When you thread it, hold the bobbin from spinning with one finger and be SURE you feel and hear the thread click into place as you follow the threading path. Also, when you thread the machine, put tension on the thread near the spool and be sure your presser foot is raised as you thread your machine. Check to be sure you are following the thread path and haven't missed a step. Hopefully I'm not insulting you but these basics can cause lots of sewing problems and they are easy mistakes to make on a new machine.
Pat