You might want to check what kind of primer you used. It's ok to put acrylic on lacquer, but not vice versa...
Another thing it COULD be...did you lightly sand the primed area before you laid your paint down? This stuff needs something to "grab" onto.
Just a thought...hope it helps.
Sand it smooth right down to the white and reprimer it, it wont hurt it. Just dont go to deep or you will get holes in the knee's from fiberglass bubbles under the gealcoat, perfectly normal but just dont go to far, if you do bondo just over them.