Arduino Pro uploading error

//Declare a name constant

const int switchPin = 8;

//Create the variable to hold the time

unsigned long previousTime = 0;

// Name variables for the inputs and outputs

int switchState = 0;
int prevSwitchState = 0;

// Create a variable named led. This will be used to control which LED is the next one to be turned on. Here, we start with pin 2.t

int led = 2;

// Declare a variable describing the interval between the events.

long interval = 600000;

// Set the direction of your digital pins
void setup() {
  for (int x = 2; x < 8; x ++) {
    pinMode(x, OUTPUT);
  }
  pinMode(switchState, INPUT);
}
// Check the time since the program started running
void loop() {

  unsigned long currentTime = millis();
  if (currentTime - previousTime > interval) {

    previousTime = interval;

    // Turn on an LED, prepare for the next one(Note: previousTime indicates the last time an LED was turned on.
    // Once you have set previoustime, turn on the LED, and increment the led variable. The next time you pass
    // the time interval, the next LED will light up

    digitalWrite(led, HIGH);
    led++;
    // Check to see if all lights are on
    if (led == 7) {
    }
  }

  // Read the value of the switch. Now that we have checked time, you will want to see if the switch has changed its state. We can read the switch value into the
  // switchState variable.


  switchState = digitalRead(switchPin);

  // Reset the variables to their default if necessary. with an if() statement, check to see if the switch is in a different position than it was previously.
  // The != evaluation checks to see if switchState does not equal to the prevSwitchState. If they are different, turned the leds off, return the led variable
  // to the first pin, and reset the the timer for LEDs by setting previousTime to currentTime.

  if (switchState != prevSwitchState) {
    for (int x = 2; x < 8; x++) {
      digitalWrite(x, LOW);
    }
    led = 2;
    previousTime = currentTime;
  }
  prevSwitchState = switchState;
}


Hi this is the code from the Arduino project book. When I tries to upload this code into the Arduino Uno(Pro), it throws the following errors message. I googled how to solve this errors but it was not
quite helpful. Any helps are greatly appreciated.

Error messages:
Arduino: 1.8.5 (Mac OS X), Board: "Arduino Pro or Pro Mini, ATmega328 (5V, 16 MHz)"

WARNING: Category '' in library EEPROM is not valid. Setting to 'Uncategorized'
WARNING: Category '' in library SPI is not valid. Setting to 'Uncategorized'
WARNING: Category '' in library SoftwareSerial is not valid. Setting to 'Uncategorized'
WARNING: Category '' in library Wire is not valid. Setting to 'Uncategorized'
Warning: platform.txt from core 'Arduino AVR Boards' contains deprecated recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{build.path}/{archive_file}" "{object_file}", automatically converted to recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{archive_file_path}" "{object_file}". Consider upgrading this core.
/Users/RAJU/Documents/Arduino/Digital_Hour_Glass_Arduino_Uno_01/Digital_Hour_Glass_Arduino_Uno_01.ino: In function 'void loop()':
/Users/RAJU/Documents/Arduino/Digital_Hour_Glass_Arduino_Uno_01/Digital_Hour_Glass_Arduino_Uno_01.ino:33:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (currentTime - previousTime > interval) {
                                    ^
Sketch uses 1228 bytes (3%) of program storage space. Maximum is 30720 bytes.
Global variables use 23 bytes (1%) of dynamic memory, leaving 2025 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00
Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Those library error tend to indicate you have a mix of old and new files. It's hard to tell if you have old libraries in your sketch folder, or in your Arduino installation, or in the Arduino15 folder.

The failure to upload may be due to a bootloader problem on your Arduino. Did it work before?