Are you able to ping your PandaBoard? If, for some reason, your host computer cannot talk to the PandaBoard. You would typically get the connection erro you see above.
To find out MATLAB can talk to your PandaBoard, execute the following on the MATLAB command line:
>> h = pandaboard
>> h.connect
If this gives you a "Connection successful" message you are good. Next, make sure that you follow the instructions in the "Getting started" demo for PandaBoard support package. This demo tells you how to do an external mode simulation.
Also examine the DOS window that opens up after the Simulink model is launched on your PandaBoard. This DOS window pipes messages coming from your PandaBoard back to the host computer. If there was an error starting your application, you would see an error message in the DOS window. For example, you do not have a camera connected to your PandaBoard but you are trying to use a V4L2 Video Capture block in your Simulink model, you would get an error.
