why cant i upload any sketches to arduino?

Projects Programming
5

I got almost the same error
I use Duemilanove ATMEGA 328
It work just find until I upload the code that seem to be the reason
after upload this code when I try to upload a new code I will get an error message;
avrdude: stk500_getsync(): not in sync: resp=0x30

First, I thought that the chip is broken so I use another arduino and right after I upload the same code, it has the same problem
here is the code;

#include <Reflector.h>
#include <Move.h>

Move move(2,3,4,5,10,11); //first four pin for each 2 input of each motor(2 motor)
                          //last two for enable input of ic
Reflector reflector(200);
int dim = 5;
int y = ((dim-1)/2) +1 ;//initial y position
int l = 0;
int r = 1;
int t = 0;

void setup(){
  Serial.begin(9600);
}

void loop(){
  
  int inten0, inten1, inten2;
  int sensor0, sensor1, sensor2;
  sensor0 = reflector.sensor(0); // analorRead pin input of each sensor
  sensor1 = reflector.sensor(1);
  sensor2 = reflector.sensor(2);
  
  inten0=reflector.reference(sensor0); 
  inten1=reflector.reference(sensor1);
  inten2=reflector.reference(sensor2);
  Serial.print(inten0);  
  Serial.print(" ");
  Serial.println(inten1);

  move.speed(100,90);
  if(inten0 == 1 && inten1 == 1 && y <dim){  
    move.forward();
    y++;
  }
  
  if(inten0 == 0 && inten1 == 1 && y == dim && r==1 ){
    move.left();
    y = 0;
    t++;
    l==1;
    r==0;
  }
  
  if(inten0 == 1 && inten1 == 0){
    move.right();
     y = 0;
    t++;
    l==0;
    r==1;
  }
  if(t==8&&y==dim){
   move.stop(); 
  }
  
 delay(50);
  }

So, anyone have any idea