Janet Gronski, The built in French Knot stitch is #6 in Decorative Stitches category on the 15k machine. That is the stitch that Diane's instructions use to modify the stitch length on.
Basically what she does is try to eliminate the long stitches that connects successive French Knots together so that it stitches just as a nice single French Knot, and she adjusts the tension so that it looks lumpy.
Adjust the length to 0.0 and the tension to 8.2 and save it in a folder you create in the machine.
The stx file that I created in Stitch Composer does much the same thing, but I feel that it stitches more successfully than the modified built-in stitch.
I'm attaching both the .stx file and Diane's instructions, I hope that's okay.
Try them both and see what you like!