Prime member or not.... I am a prime member

I was checking out and applied the coupon that should give me 25% of my $20 or more as said in the newsletter:

*** All Members save 25% on your next purchase of $20 or more:***

Enter Discount Code 12092011B20P25 at Checkout · Expires Dec 12, 2011

with items of $21.83 the cart say I don't meet the minimum purchace :o(

I'd say I met it with + $1.83 !!