I couldn't get the links to work either.
Based on Nick's quote, the control box acts as a DCE device. Your computer's port is wired as a DTE device. Thus you cannot use the same cable to talk to both from the Arduino, unless you re-configure the Arduino end.
If you used a null-modem cable to talk to the computer, you need a straight-through cable to talk to the controller, and vice versa. Or you need to change the Arduino end from DTE to DCE or vice versa.
That's just the tip of the iceberg on settings to check for successful RS232 comm.
I suggest doing what WildBill suggested and communicate with the box using Hyperterminal first to confirm the controller is working as expected.