Serial monitor is not working

Hi all,

This morning, I tested a self made satellite by sending its data to the serial monitor.
The project worked great! Later that day, I added an extra sensor. Shortly after that, I tested the whole project, but suddenly the serial monitor stopped showing its data.
At first I thought the last sensor wasn't connected well, but then I saw this:

java.io.IOException: jssc.SerialPortException: Port name - COM3; Method name - setEventsMask(); Exception type - Can't set mask.
 at processing.app.Serial.dispose(Serial.java:144)
 at processing.app.SerialMonitor.close(SerialMonitor.java:108)
 at processing.app.AbstractMonitor.suspend(AbstractMonitor.java:96)
 at processing.app.Editor$DefaultExportHandler.run(Editor.java:2182)
 at java.lang.Thread.run(Thread.java:745)
Caused by: jssc.SerialPortException: Port name - COM3; Method name - setEventsMask(); Exception type - Can't set mask.
 at jssc.SerialPort.setEventsMask(SerialPort.java:279)
 at jssc.SerialPort.removeEventListener(SerialPort.java:1064)
 at jssc.SerialPort.closePort(SerialPort.java:1090)
 at processing.app.Serial.dispose(Serial.java:141)
 ... 4 more

I thought the error was caused by the Arduino itself.
However, I decided to desolder the last sensor but the problem was still there...

Does someone know how to solve this problem?

Thanks in advance,

Vierus

You would have to include a schematic and decent pictures and possibly the sketch involved to get better responses.