Arduino Modbus Slave no matching function for call to 'modbusSlave::setBaud(int)'

Hello everyone,
I'm trying to set up an Arduino Nano into a Modbus RTU slave over RS232 using that library http://code.google.com/archive/p/arduino-modbus-slave/downloads
yet, whenever i try to compile the code, i get the following error:

no matching function for call to 'modbusSlave::setBaud(int)'

highlighting the line where "slave.setBaud(9600);" is, although when i see example sketches of that library and those that are similar, it's always written as such, so I wonder what could be wrong in my code or anywhere in the library.

Here is my code where i try to toggle two LEDs

#include <modbusSlave.h>
#include <modbusDevice.h>
#include <modbus.h>
#include <modbusRegBank.h>

modbusDevice regBank;
modbusSlave slave;

#define LED1 2
#define LED2 3

void setup()
{   
//Assign the modbus device ID.  
  regBank.setId(1);

/*
modbus registers follow the following format
00001-09999  Digital Outputs, A master device can read and write to these registers
10001-19999  Digital Inputs, A master device can only read the values from these registers
30001-39999  Analog Inputs, A master device can only read the values from these registers
40001-49999  Analog Outputs, A master device can read and write to these registers 

Analog values are 16 bit unsigned words stored with a range of 0-32767
Digital values are stored as bytes, a zero value is OFF and any nonzer value is ON

*/
  regBank.add(1);
  regBank.add(2);

  slave._device = &regBank;  
  slave.setBaud(9600);

  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);    
}

void loop()
{
  while(1){
    int DO1 = regBank.get(1);
    if (DO1 <= 0 && digitalRead(LED1) == HIGH) digitalWrite(LED1, LOW);
    if (DO1 >= 1 && digitalRead(LED1) == LOW) digitalWrite(LED1, HIGH);
    int DO2 = regBank.get(2);
    if (DO2 <= 0 && digitalRead(LED2) == HIGH) digitalWrite(LED2, LOW);
    if (DO2 >= 1 && digitalRead(LED2) == LOW) digitalWrite(LED2, HIGH);
  slave.run();  
} 
}

I'm using Arduino IDE 1.8.9

Any help greatly appreciated

/MaverickRF

Do the example sketches compile ?

This one compiles successfully without any error

#include <modbus.h>
#include <modbusDevice.h>
#include <modbusRegBank.h>
#include <modbusSlave.h>

/*
This example code shows a quick and dirty way to get an
arduino to talk to a modbus master device with a
device ID of 1 at 9600 baud.
*/

//Setup the brewtrollers register bank
//All of the data accumulated will be stored here
modbusDevice regBank;
//Create the modbus slave protocol handler
modbusSlave slave;

void setup()
{   

//Assign the modbus device ID.  
  regBank.setId(1);

/*
modbus registers follow the following format
00001-09999  Digital Outputs, A master device can read and write to these registers
10001-19999  Digital Inputs, A master device can only read the values from these registers
30001-39999  Analog Inputs, A master device can only read the values from these registers
40001-49999  Analog Outputs, A master device can read and write to these registers 

Analog values are 16 bit unsigned words stored with a range of 0-32767
Digital values are stored as bytes, a zero value is OFF and any nonzer value is ON

It is best to configure registers of like type into contiguous blocks.  this
allows for more efficient register lookup and and reduces the number of messages
required by the master to retrieve the data
*/

//Add Digital Output registers 00001-00016 to the register bank
  regBank.add(1);
  regBank.add(2);
  regBank.add(3);
  regBank.add(4);
  regBank.add(5);
  regBank.add(6);
  regBank.add(7);
  regBank.add(8);
  regBank.add(9);
  regBank.add(10);
  regBank.add(11);
  regBank.add(12);
  regBank.add(13);
  regBank.add(14);
  regBank.add(15);
  regBank.add(16);

//Add Digital Input registers 10001-10008 to the register bank
  regBank.add(10001);  
  regBank.add(10002);  
  regBank.add(10003);  
  regBank.add(10004);  
  regBank.add(10005);  
  regBank.add(10006);  
  regBank.add(10007);  
  regBank.add(10008);  

//Add Analog Input registers 30001-10010 to the register bank
  regBank.add(30001);  
  regBank.add(30002);  
  regBank.add(30003);  
  regBank.add(30004);  
  regBank.add(30005);  
  regBank.add(30006);  
  regBank.add(30007);  
  regBank.add(30008);  
  regBank.add(30009);  
  regBank.add(30010);  

//Add Analog Output registers 40001-40020 to the register bank
  regBank.add(40001);  
  regBank.add(40002);  
  regBank.add(40003);  
  regBank.add(40004);  
  regBank.add(40005);  
  regBank.add(40006);  
  regBank.add(40007);  
  regBank.add(40008);  
  regBank.add(40009);  
  regBank.add(40010);  
  regBank.add(40011);  
  regBank.add(40012);  
  regBank.add(40013);  
  regBank.add(40014);  
  regBank.add(40015);  
  regBank.add(40016);  
  regBank.add(40017);  
  regBank.add(40018);  
  regBank.add(40019);  
  regBank.add(40020);  

/*
Assign the modbus device object to the protocol handler
This is where the protocol handler will look to read and write
register data.  Currently, a modbus slave protocol handler may
only have one device assigned to it.
*/
  slave._device = &regBank;  

// Initialize the serial port for coms at 9600 baud  
  slave.setBaud(9600);   
}

void loop()
{
//put some data into the registers
  regBank.set(1, 1);  
  regBank.set(2, 1);  
  regBank.set(3, 0);  
  regBank.set(4, 1);  
  regBank.set(5, 1);  
  regBank.set(6, 0);  
  regBank.set(7, 1);  
  regBank.set(8, 0);  

  regBank.set(10001, 1);
  regBank.set(10002, 1);  
  regBank.set(10003, 1);  
  regBank.set(10004, 1);  
  regBank.set(10005, 0);  
  regBank.set(10006, 0);  
  regBank.set(10007, 0);  
  regBank.set(10008, 0);  


  regBank.set(30001,1);
  regBank.set(30002,2);
  regBank.set(30003,3);
  regBank.set(30004,4);
  regBank.set(30005,5);
  regBank.set(30006,6);
  regBank.set(30007,7);
  regBank.set(30008,8);
  regBank.set(30009,9);
  regBank.set(30010,10);

  regBank.set(40001,1);
  regBank.set(40002,2);
  regBank.set(40003,2);
  regBank.set(40004,4);
  regBank.set(40005,5);
  regBank.set(40006,6);
  regBank.set(40007,7);
  regBank.set(40008,8);
  regBank.set(40009,9);
  regBank.set(40010,10);
  
 while(1)
  {
    //put a random number into registers 1, 10001, 30001 and 40001
    regBank.set(1, (byte) random(0, 2));
    regBank.set(10001, (byte) random(0, 2));
    regBank.set(30001, (word) random(0, 32767));
    regBank.set(40001, (word) random(0, 32767));
    
     slave.run();  
  }
}

Your sketch in your original post compiles for me

Weird,huh? Also, I've tried to start from the example, modifying it and not copying it to another sketch and it compiles well.
What could be the cause of that?