It is so frustrating to find an error in a pattern . . . and more so when it is one of your own! Note to self -- the more familiar the design element (in this case, the simple Granny Square) -- the easier it is to goof up.
If you purchased through Ravelry, please download the corrected pdf file.
If you have a printed pattern, please note the following corrections:
replace Round 4 with the corrected version below:
Round 4 – end: Beg corner, ch 2, (sc, ch 2) in each ch-2 sp across to next corner sp, * corner, ch 1, (3 dc, ch 1) in each ch-1 sp across to next corner sp, repeat from * two more times, join round.
Make the following correction in the paragraph directly below round 4:
Subsequent rounds are worked as for round 4, where the first side of the square is worked with one single crochet into each chain-2 space and 2 chains between each single crochet.