exit status 1 'Motor1' was not declared in this scope

greating this is a simple program for control 4wd car (dc motors)
but have error i anyones want to give a advice thanks a lot....
exit status 1
'Motor1' was not declared in this scope

#include <AFMotor.h>

AF_DCMotor g_motor1(1, MOTOR12_8KHZ); // back left
AF_DCMotor g_motor2(2, MOTOR12_8KHZ); // back right
AF_DCMotor g_motor3(3, MOTOR12_8KHZ); // front right
AF_DCMotor g_motor4(4, MOTOR12_8KHZ); // front left
void setup()
{
}

void loop()
{
  Motor1.setSpeed(255);
//exit status 1
'Motor1' was not declared in this scope

  Motor2.setSpeed(255);
  Motor3.setSpeed(255);
  Motor4.setSpeed(255);
  Motor1.run(FORWARD);
  Motor2.run(FORWARD);
  Motor3.run(FORWARD);
  Motor4.run(FORWARD);
  delay(1000);
  Motor1.run(BACKWARD);
  Motor2.run(BACKWARD);
  Motor3.run(BACKWARD);
  Motor4.run(BACKWARD);
  delay(1000);
  Motor1.run(FORWARD);
  Motor2.run(BACKWARD);
  Motor3.run(BACKWARD);
  Motor4.run(FORWARD);
  delay(1000);
  Motor1.run(BACKWARD);
  Motor2.run(FORWARD);
  Motor3.run(FORWARD);
  Motor4.run(BACKWARD);
  delay(1000);
  Motor1.setSpeed(0);
  Motor2.setSpeed(0);
  Motor3.setSpeed(0);
  Motor4.setSpeed(0);
  Motor1.run(BRAKE);
  Motor2.run(BRAKE);
  Motor3.run(BRAKE);
  Motor4.run(BRAKE);

  delay(1000);
}

I don't see anything called Motor1, and neither does the compiler.
Did you mean "g_motor1"?

And same with Motor2, Motor3 and Motor4 I guess.

Make "g_motor1" match every "Motor1" by either changing one or the other to be the same thing.
Although this stuff is case(capitalization) sensitive, so it's preferable to keep it "motor1", "motor2", etc.