USB Serial Port Unplug Notice

Hello!

I'm trying to send few data via serial port to my arduino. Thnings work fine, after a few seconds in get the warning: "USB Serial Port Unplug Notice" and the connection is closed. I downloaded the newest Processing, RXTX-2.1-7. The console write the following lines: java.io.IOException: Device not configured in writeByte
at gnu.io.RXTXPort.writeByte(Native Method)

Anyone knows answers?

Greets