no device found on ttymxc3(Arduino IDE)

As title, I want to use arduino to control LED on udoobuntu. I follow this example(http://www.udoo.org/tutorial/getting-started-with-arduino-ide-on-udoo/), but there is something wrong(error.jpg). I remove the oringinal Arduino IDE and install Arduino, but it didn't work. Please help me. Thanks!

 

Please try UDOObuntu 2 beta, things have been improved a lot.

 

to Francesco:

I tried UDOObuntu 2 beta, but it didn't work.

 

I change new board and it works... Maybe previous one have some problem.