Well, now we r supposed to use Nxt for a week, reporting all found serious bugs...
Pay attention to Time difference between nodes. If it's outside of +/-15 sec frame, then we could see unsynchronization of the network.
One important note: If ur node is visible on the Internet then launch client by
java -cp Nxt.zip Nxt IP_ADDRESS
Right now only 1 bootstrapping node runs the newest version. If it goes down the network will be fragmented.