Hi Eileen,
It could be that the sponge bar is worn - there should be about a quarter of an inch of foam above the metal.
It could be that your tension is too loose.
You do not say whether you are knitting on the singlebed or ribber. If singlebed do not try to knit over every needle to start.
Try every other needle at a tight tension. Knit 1 row.
Hang on the cast-on comb. Push forward the in-between needles, loosen the tension and knit across. All the needles should now have either a loop of yarn or a completed stitch.
Hope this helps to get you started.
Sue, October 2009