Arduino Starter Kit Error Message

I have just purchased an Arduino starter kit and written my first sketch on page 37 of the 'projects book'.
The sketch, shown below, was copied from the book but when I try to 'verify' the sketch line 2 becomes highlighted and I get an error message "expected unqualified-id before numeric constant"

1 int switchState = 0;
2 void setup() {
3 pinMode(3,OUTPUT);
4 pinMode(4,OUTPUT);
5 pinMode(5,OUTPUT);
6 pinMode(2,INPUT);
7}
8 void loop(){
9 switchState=digitalRead(2);
10//not comment
11 if (switchState==LOW){
12 //the button is not pressed

13 digitalWrite(3,HIGH); //green LED
14 digitalWrite(4,LOW); //red LED
15 digitalWrite(5,LOW); //red LED
16 }
17 else { // the button is pressed
18 digitalWrite(3,LOW);
19 digitalWrite(4,LOW);
20 digitalWrite(5,HIGH);

21 delay(250); //wait for a quarter second
22 //toggle the LEDs
23 digitalWrite(4,HIGH);
24 digitalWrite(5,LOW);
25 delay(250); //wait for a quarter second

26 }
27 } //go back to beginning of loop

Does anyone know what this means and how I can proceed?
Any help will be greatly appreciated!

The line numbers in the book are NOT supposed to be typed in.

That was the problem alright- your help was greatly appreciated!