Android Question error message in felUsbSerial example

Hello, I"m using the felUsbSerail jar to connect tablet to usb port, which in his turn connect to microchip serial device.

the app connect to the device, and ask for permission, but when I click "connect" it crushes...

this is the LOG-
--------- beginning of main
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
Resume
** Activity (main) Pause, UserClosed = false **
--------- beginning of system
** Activity (main) Resume **
Resume
Number of devices: 1
Ready to start...
Buffer size: 16384
Error occurred on line: 74 (Main)
java.lang.RuntimeException: Error opening serial device.
at anywheresoftware.b4a.objects.usb.felUsbSerial.Initialize2(felUsbSerial.java:82)
at anywheresoftware.b4a.objects.usb.felUsbSerial.Initialize(felUsbSerial.java:62)
at b4a.example.main._btnconnect_click(main.java:535)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:348)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:180)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at anywheresoftware.b4a.objects.ViewWrapper$1.onClick(ViewWrapper.java:80)
at android.view.View.performClick(View.java:5624)
at android.view.View$PerformClick.run(View.java:22441)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6316)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:872)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:762)