OVEN TO 400 °F (195 °C). Remove filo pastry from freezer and let it come to room temperature while you prepare the filling.
Unfold the dough, and cut the stack of sheets in two. If you are making just one recipe, refold half the dough, and wrap it in plastic. It can either be refrozen or kept for a few days in the refrigerator. Cover the sheets to be used with a sheet of waxed paper covered in turn with a damp kitchen towel, to keep them from becoming dry and brittle.
Grate the zucchini on the large holes of a hand grater or in a food processor. Toss with the salt and set aside for 30 minutes. Then drain and squeeze dry in a clean kitchen towel.
Roast the pine nuts for 5-8 minutes in oven, chop them finely, and set them aside. Heat the olive oil in a large skillet and sauté the onion until it begins to soften, about 2 minutes.
Add the zucchini, season with freshly ground black pepper, and cook another 4 minutes; then add the garlic, basil, parsley and white wine or water. Cover for 3 to 4 minutes, and remove from heat.
Beat the eggs, stir in the cheeses, then cook the vegetables. Check the seasoning.
Brush a 9x13" pan with the melted butter and lay a sheet of filo pastry with butter, or mixture of butter and olive oil, and continue buttering and layering, until you have used half the sheets.
Scatter half of the chopped pine nuts between several of the layers. Brush the top layer with butter and spread the filling over it.
Continue layering the rest of the pastry sheets. If the butter begins to congeal, reheat it so it spreads easily.
Cut the assembled pastry into 3" squares, then into diamonds, making sure you cut through all the layers; refrigerate the pastry if you will not be baking right away.
Bake until browned, about 40 to 50 minutes. Serve the pastries warm from the oven, slightly cooled, or at room temperature. Makes one 9x13" filo pastry.