Pattern Corrections are as follows:
Rnd 3 - after the following text ‘Join dk red with sc in any stitch’ do sc in next 3 sts then continue and replace the ‘2 sc in next stitch, sc in next stitch’ with sc in next 3 sts.

Rnd 4 - after ch 3 skip 1 st, cluster in next stitch - and repeat around. (only skipping 1 stitch between clusters).

Rnd 6 - where it says 2 dc in next space do 3 dc - this will be after and before each corner (you need the extra stitches you are creating here, they come into play in round 9).
The round should end with 3 dc in the last space and a final dc in the next cluster before joining to begining 3 ch.