No Serial Monitor output from sketch using Bridge library

[per1234]

Moved from arduino/Arduino#3298 by @IvanKunjasic

I try to upload simple Bridge sketch to my Arduino YUN, but i didn't get any Serial Monitor output.
http://www.arduino.cc/en/Tutorial/Bridge

Also, on two separate Arduino Yuns on two separate laptops, I can't get JsonParserExample(aJSON) to Run. I just get no output in the Serial Monitor. And if I change the lines

if (!root.success()) {
Serial.println("parseObject() failed");
return;
}

to

if (!root.success()) {
Serial.println("parseObject() failed");
return;
} else {
Serial.println("Success!");
}

I still get nothing from the Serial Monitor.

I've checked the Baud Rates. I've run Examples>04.Communication>SerialCallResponse and the Serial Monitor works fine there.

Any clue?