Sending data through Socket leads to lock-up

Newbie & Debugging Questions
#1

Whilst working on my engine I noticed something a little odd.

For data transferring I am using TCP. About 60-times a second the client will send a packet containing it’s positional information to the server, and 60 times a second the server sends out positional packets of all entities in the world to all clients.

I know, 60 times a second is overkill! I will reduce this later on (unless it is what’s causing the problem).

After anywhere from 10 - 20 seconds my client seems to lock up when it tries to send data to the server. Here is the send method:

/**
 * This method writes a packet of data to a socket.
 * @param packet
 */
public void send(Packet packet) {
	if (closed)
		return;
	
	if (!socket.isConnected()) {
		close();
		return;
	}
	
	try{
		byte[] ba = packet.buffer.getOutgoing();
		out.write(ba.length & 0xFF);
		out.write(ba.length >> 8 & 0xFF);
		out.write(ba);
		out.flush();
		bytesSent += ba.length + 2;
	}catch(Exception e) {
		close();
	}
}

What’s odd, is that this ONLY happens when I run both the client and server application on my desktop computer. If I connect to my server computer from the client, this does not happen.

Any ideas? o: