Hmm this looks awfull familiar to me. Do you tighten all your stitches very much?
Does the extra yarn get more with every stitch you knit?
This could be because you tighten your stitches too much, atleast that's what I did when I began knitting. Try to knit them a bit looser as not to carry that extra yarn with you(oh god, that's hard to describe :rollseyes: ).
Or try as the others mentioned, another cast on method.