BROOKLYN - A cultural celebration of folklore, dance and music from six Latin-American and Caribbean nations is being held in Fort Greene this weekend.The Hispanic Heritage Festival started yesterday and will continue tonight at the Brooklyn Music School, welcoming performers from Colombia, Cuba, the Dominican Republic, Mexico, Panama and Puerto Rico. The festival is an initiative of the Brooklyn Music School's Cultural Dance Division to promote the awareness and participation in the cultural diversity of Brooklyn and its Hispanic communities."It helps to intertwine the fabric of this community and of the populations in New York City," says Executive Director of the Brooklyn Music School Frank Alvarado.