Code:

	public void updateNPCMovement(stream str) {
		if(updateRequired || direction != -1) {
			System.out.println("sends = "+direction);
			str.writeBits(1, 1);
			/**
			 * self Update type is sent as 2 bits.
			 * Only one of these is sent at once.
			 * 0: No data to send
			 * 1: 3 bits for direction then 1 bit for update required (?)
			 * 2: 3 bits for 1st dir, 3 bits for 2nd dir, then 1 bit for update required (?)
			 */
			if(direction != -1) {
				if(false) {
					str.writeBits(2, 2); // update type 2
					str.writeBits(3, Mobs.CLIENT_SPRITES[0]); // direction 1
					str.writeBits(3, Mobs.CLIENT_SPRITES[direction]); // direction 2
					str.writeBits(1, updateRequired ? 1 : 0); // is the update required?
				} else {
					str.writeBits(2, 1); // update type 1
					str.writeBits(3, Mobs.CLIENT_SPRITES[direction]); // direction
					str.writeBits(1, updateRequired ? 1 : 0); // is the update required?
				}
			} else {
				str.writeBits(2, 0); //don't need to move and an update is required
			}
		} else {
			str.writeBits(1, 0);
		}
	}


When landed on the println msg:

Error: arch337 size mismatch in getnpcpos - pos:18 psize:20
Error: T2 - 65,81,124 - 20,2609,3103 - 21,1,0,1,-1,-8,84,71,19,1,-3,127,0,0,0,3,
99,20,63,24,
Exception in thread "Thread-3" java.lang.NullPointerException
        at client.build3dScreenMenu(client.java:6133)
        at client.processRightClick(client.java:8180)
        at client.draw3dScreen(client.java:11154)
        at client.method146(client.java:14758)
        at client.drawGameScreen(client.java:10081)
        at client.processDrawing(client.java:11053)
        at RSApplet.run(RSApplet.java:117)
        at client.run(client.java:6021)
        at java.lang.Thread.run(Unknown Source)