Example. Cant start. net.wimpi.modbus.net.SerialConnection.open(SerialConnection.java:91)

[Alexey]

Hello.
I have code
//import java.net.;
//import java.io.;
import net.wimpi.modbus.;
import net.wimpi.modbus.msg.;
import net.wimpi.modbus.io.;
import net.wimpi.modbus.net.;
import net.wimpi.modbus.util.*;

public class mbTest {

public static void main(String[] args) {
try {
/ The important instances of the classes mentioned before /
SerialConnection con = null; //the connection
ModbusSerialTransaction trans = null; //the transaction
ReadInputRegistersRequest req = null; //the request
ReadInputRegistersResponse res = null; //the response

    /* Variables for storing the parameters */
//  String portname= null; //the name of the serial port to be used
    int unitid = 3; //the unit identifier we will be talking to
    int ref = 100; //the reference, where to start reading from
    int count = 15; //the count of IR's to read
    int repeat = 1; //a loop for repeating the transaction

    //2. Set master identifier

// ModbusCoupler.createModbusCoupler(null);
ModbusCoupler.getReference().setUnitID(1);

    //3. Setup serial parameters
    SerialParameters params = new SerialParameters();
    params.setPortName("/dev/ttyUSB0");
    params.setBaudRate(19200);
    params.setDatabits(8);
    params.setParity("Even");
    params.setStopbits(1);
    params.setEncoding("tru");
    params.setEcho(false);

    //4. Open the connection
    con = new SerialConnection(params);
    con.open();

    //5. Prepare a request
    req = new ReadInputRegistersRequest(ref, count);
    req.setUnitID(unitid);
    req.setHeadless();

    //6. Prepare a transaction
    trans = new ModbusSerialTransaction(con);
    trans.setRequest(req);

    //7. Execute the transaction repeat times
    int k = 0;
    do {
      trans.execute();
      res = (ReadInputRegistersResponse) trans.getResponse();
      for (int n = 0; n < res.getWordCount(); n++) {
        System.out.println("Word " + n + "=" + res.getRegisterValue(n));
      }
      k++;
    } while (k < repeat);

    //8. Close the connection
    con.close();

} catch (Exception ex) {
  ex.printStackTrace();
}

}

}

But I have exeption 91.
java.lang.Exception
at net.wimpi.modbus.net.SerialConnection.open(SerialConnection.java:91)

What it means?
How fix it?

[Alexey]

my jars

[Bram Bouwens]

Please note that it isn't Exception 91, but an Exception in line 91 of SerialConnection.
You should consider the j2mod variant of Steve O'Hara though.