No longer ignoring .png files, thanks Mario.

src/model/Board.java

@@ -18,7 +18,8 @@ public class Board {
 	private int numPlies = 0;
 
 	public Board(Board that) {
-		this();
+		board = new TileColor[NUM_ROWS][NUM_COLS];
+		
 		for (int i = 0; i < NUM_COLS; i++) {
 			for (int j = 0; j < NUM_ROWS; j++) {
 				this.board[j][i] = that.board[j][i];

src/player/generator/AlphaBetaMoveGenerator.java

@@ -12,7 +12,7 @@ import org.apache.log4j.Logger;
 public class AlphaBetaMoveGenerator implements MoveGenerator {
 	private static final Logger LOGGER = Logger
 			.getLogger(AlphaBetaMoveGenerator.class.getName());
-	private static final int DEFAULT_RECURSIVE_PLAYS = 2;
+	private static final int DEFAULT_RECURSIVE_PLAYS = 3;
 
 	private final BoardScorer scorer = new BoardScorer();
 	private final ValidMoveGenerator validMoveGenerator = new ValidMoveGenerator();

src/player/generator/ValidMoveGenerator.java

@@ -27,8 +27,11 @@ public class ValidMoveGenerator implements MoveGenerator {
 			for (int j = 0; j < Board.NUM_COLS; j++) {
 				if (board.getTile(i, j) == TileColor.NONE) {
 				for (TileColor color : TileColor.values()) {
+					if (color == TileColor.NONE) {
+						continue;
+					}
 					validMoves.add(new Move(color, i, j));
-				}
+					}
 				}
 			}
 		}