Originally Posted by Ingrid
Are you knitting your tail in with the first row? Maybe you should try without.
That looks like your slip knot hanging there. Do you knit it?
Another thought--instead of using a slip knot, just drape the yarn over the needle before you make your first cast on stitch. You'll get two in one for this cast on and if the slip knot is the problem, you'll eliminate it. If it's not, then you can maybe focus on something else.
I have the feeling that the slip knot itself is the problem, since it seems to stem from there. I made sure to not knit the tail in with the first row - that happened by accident once and it threw my stitches off. I make sure to not knit the slip knot; because of that extra loop, it doesn't really knit well at all.