How is the thread wound on the spool? Make sure there is no drag on thread and it is coming off the spool easily.
Does your machine have a speed control? Try stitching slower.
Next try using a longer stitch length.
Is your machine stitching OK with other samples?
Did you use basting spray or glue on the quilt sandwich?
These can all factor in to machines mis-behaving. Hope that helps a bit.