It could be that you did the YO after you made a new knit stitch, but before you pulled the loop through... I'm totally guessing, BTW. Here is a link to Amy's scarf pattern page: the third one down on the left hand side is made with elongated stitches, which is what I guessed you mihg tbe doing. If youhave time, check it out, and check out the video (which is right under the picture), and see if it's the same. If it is, we found the solution to the problem, and if not, you've learned something new anyway!