when i thread my machine the thread is getting hung up as soon as it is pulled around to the front screw on the bobbin case. the area directly in froont of the bottom thread feed. when i took it apart to see what was catching it i see an opening directly above the screw in the center (painted green)an i can't tell if there is a piece broken off or if it was alway open like that. anyone know if that is a solid circle or where i can view a diagram of those parts? emergency! have costumes that must be done for halloween and i am stressing!