Atmega 328P pin 0 as input errors

Other Hardware 3rd Party Boards
5 
string ID;
void setup() {
  SPI.begin();
  pinMode(0, INPUT);
  pinMode(7, INPUT);
  pinMode(8, OUTPUT);
  digitalWrite(0, HIGH);
  digitalWrite(8, LOW);  
  rfid.PCD_Init();
  backtime = millis();
}
void loop() {
	if(digitalRead(0)==LOW && strID==ID){
		digitalWrite(8, HIGH);
	}
 if (!rfid.PICC_IsNewCardPresent() || !rfid.PICC_ReadCardSerial() && azonositas==true){return;}
  String strID = "";
  for (byte i = 0; i < 4; i++) {
    strID +=
      (rfid.uid.uidByte[i] < 0x10) +
      String(rfid.uid.uidByte[i])
      ;
  }

  strID.toUpperCase();

photo:
https://drive.google.com/file/d/0ByjewCSevUMZVWVueW5QS0w3YU0/view