Hmm... I have not heard of the "Curse of the Goddess" in these terms before.... nor have I read the Book Of Shadows that it speaks of. Then again, I'm not a Wiccan. Perhaps I cannot speak of this then, but I will tell you what it means to my "ecclectic" faith:
The Curse of the Goddess is a blessing as well, a double-edged sword. When one commits themselves to one Goddess (or aspect of the Goddess), they are rewarded with some of the Divine Powers thereof; yet, neglected of that which those things can bring. It is to serve a purpose without the pleasure of doing so.
Say one should swear by the Moon Goddess... they could have the wisdom of Nokomis to share insights that another may understand and be better, but never will they quench their search of knowledge.... they will never find in this life that which they seek, though they will bring this to others. They could have the unconditional love of Selene, but never shall they the love in partnership of another. They can teach others to love this way (even to love that which teaches), but it shall always be found in another.... never the one who swears by such things. It is a way of life, a curse and a blessing.
Sorry if that got off topic, but that is the only time I've heard of such a thing.