Problem using 12C scanner code on Arduino Nano V3

Notice: I'm a Noob. Pls don't hurt me.

I downloaded the code (below) in order to learn the I2C info for the components connected to the Nano pins A4 and A5.

// --------------------------------------
// i2c_scanner
//
// Version 1
//    This program (or code that looks like it)
//    can be found in many places.
//    For example on the Arduino.cc forum.
//    The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
//     Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26  2013
//    V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
//    by Arduino.cc user Krodal.
//    Changes by louarnold removed.
//    Scanning addresses changed from 0...127 to 1...119,
//    according to the i2c scanner by Nick Gammon
//    https://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
//    As version 4, but address scans now to 127.
//    A sensor seems to use address 120.
// Version 6, November 27, 2015.
//    Added waiting for the Leonardo serial communication.
// 
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//

#include <Wire.h>


void setup()
{
  Wire.begin();

  Serial.begin(9600);
  while (!Serial);             // Leonardo: wait for serial monitor
  Serial.println("\nI2C Scanner");
}


void loop()
{
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for(address = 1; address < 127; address++ ) 
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16) 
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");

      nDevices++;
    }
    else if (error==4) 
    {
      Serial.print("Unknown error at address 0x");
      if (address<16) 
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  delay(5000);           // wait 5 seconds for next scan
}

But each time I do it, I get the following error. I have checked each of my connections and the code itself appears to be in working order. Is it the Arduino itself? Am I missing something really basic here?

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x94
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x94

The error follows this pattern until it reaches 10 below.

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x94

Which Nano board is it ?
Is it an official Arduino board or a clone ? Could you show a picture of it ? of both sides ?
Has it worked before ?
Can you remove all the wires and try the Blink example ?

The official Nano board got a new bootloader. So there is the old and the new bootloader.
A Nano clone uses often a CH340G chip (you can read that on the chip). You need an extra driver for those.
A few years ago, many cheap nano boards had a counterfeit chip that got more or less disabled by the driver (search for FTDI-gate).
I read recently a few times that a Nano board did not work, because of a corrupt or missing bootloader. Probably changing the old bootloader for the new bootloader went wrong.
Almost every Nano board has a design flaw: a diode from the /RESET pin to VCC is missing. That makes it possible that the DTR signal raises the voltage of the /RESET pin causing to enter the High Voltage programming mode. That can corrupt the bootloader.

The Arduino Uno does not have so many problems.