error in the program

this is a program that senses rpm and actuates servo motor according to the rpm. im having trouble with the error message here.

Error msg is:

Servo\Servo.cpp.o: In function __vector_11': F:\Backup\arduino-1.0.5-windows\arduino-1.0.5\libraries\Servo/Servo.cpp:103: multiple definition of __vector_11’
sketch_jun18a.cpp.o:F:\Backup\arduino-1.0.5-windows\arduino-1.0.5/sketch_jun18d.ino:64: first defined here

program is:

#include <Servo.h>
Servo myservo;

int ledPin = 13; // IR LED connected to digital pin 13
#define ledPin 5
volatile byte rpmcount;
unsigned int rpm;
unsigned long timeold;

// include the library code:
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

void rpm_fun()
{
//Each rotation, this interrupt function is run twice, so take that into consideration for
//calculating RPM
//Update count
rpmcount++;
}

void setup()

{
myservo.attach(3);
pinMode(ledPin, OUTPUT);

// initialize timer1
noInterrupts(); // disable all interrupts
TCCR1A = 0;
TCCR1B = 0;
TCNT1 = 0;

OCR1A = 0.5; // compare match register 16MHz/256/2Hz
TCCR1B |= (1 << WGM12); // CTC mode
TCCR1B |= (1 << CS12); // 256 prescaler
TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt
interrupts(); // enable all interrupts

lcd.begin(16, 2); // intialise the LCD

//Interrupt 0 is digital pin 2, so that is where the IR detector is connected
//Triggers on FALLING (change from HIGH to LOW)
attachInterrupt(0, rpm_fun, FALLING);

//Turn on IR LED
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, HIGH);

rpmcount = 0;
rpm = 0;
timeold = 0;
}

ISR(TIMER1_COMPA_vect) // timer compare interrupt service routine
{
digitalWrite(ledPin, digitalRead(ledPin) ^ 1); // toggle LED pin
}

void loop()
{
//Update RPM every second
delay(1000);
//Don’t process interrupts during calculations
detachInterrupt(0);
//Note that this would be 60*1000/(millis() - timeold)rpmcount if the interrupt
//happened once per revolution instead of twice. Other multiples could be used
//for multi-bladed propellers or fans
rpm = 30
1000/(millis() - timeold)*rpmcount;
timeold = millis();
rpmcount = 0;

//Print out result to lcd
lcd.clear();
lcd.print(“RPM=”);
lcd.print(rpm);

if (rpm>1500)
{
myservo.write(90);
}
else if(rpm>1400)
{
myservo.write(80);
}
else if(rpm>1200)
{
myservo.write(70);
}
else if(rpm>1000)
{
myservo.write(60);
}
else if(rpm>800)
{
myservo.write(50);
}
else if(rpm>600)
{
myservo.write(40);
}
else if(rpm>200)
{
myservo.write(30);
}
else if(rpm>100)
{
myservo.write(20);
}
else if(rpm>50)
{
myservo.write(10);
}
else if(rpm<50)
{
myservo.write(0);
}

//Restart the interrupt processing
attachInterrupt(0, rpm_fun, FALLING);
}

The servo library uses the same timer interrupt ( __vector_11 ).

ISR(TIMER1_COMPA_vect)          // timer compare interrupt service routine
{
  digitalWrite(ledPin, digitalRead(ledPin) ^ 1);   // toggle LED pin
}

What Arduino are you using?

Thank you. im using arduino- UNO.