Holes in my Socks

I am attempting at my first sock using the magic loop method. I have followed the instructions in the Magic Loop booklet and i am almost to the toe and i am very pleased how it is comming out (working a sock IS like magic!) Anyhoo looking back at my sock i noticed that on both sides of my sock i have a small hole on the upper left and right side of the heel. I wish i had a picture of my problem but my camera is on loan. Anyone know if there is anything i can do to avoid the holes on both sides?

Picking up an extra stitch in the gap before your instep stitches should help.

Thanks i will try that with my second sock!