1. Arduino Matlab GUI controlling an LED

hi iahave a probleme whene i download the suoort package for arduino in matlab
''error open zip file

I bought your ebook, I have tried this. Did everything I was supposed to do and I got this error... How can I fix this?
Error using led_control_led_control_OutputFcn (line 77)
Failed to open serial port COM3 to communicate with board Uno. Make sure there is no other MATLAB arduino object for this board.
For troubleshooting, see Arduino Hardware Troubleshooting.

Error in gui_mainfcn (line 264)
feval(gui_State.gui_OutputFcn, gui_hFigure, [], gui_Handles);

Error in led_control (line 42)
gui_mainfcn(gui_State, varargin{:});

When I run it a message is displayed on the command window. "Undefined function 'writeDigitalPin' for input arguments of type 'double'." Do you know what that means?