Error LCD programming

Hey guys, I'm trying to write very simple program for my LCD and it has 2 errors maybe anyone could help to me?

CODE

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
lcd.init(); // initialize the lcd

// Print a message to the LCD.
lcd.backlight();
lcd.print("Hello, world!");
}

void loop()
{
}

ERRORS:

sketch_jan04a:7: error: 'LiquidCrystal_I2C' does not name a type
sketch_jan04a.ino: In function 'void setup()':
sketch_jan04a:11: error: 'lcd' was not declared in this scope

Have you installed the LiquidCrystal_I2C library. I'm guessing that it's not being found.

In case you need it, This tells you how to install libraries

And I think This is the library you need.

I done it and now i have other error:
avrdude: stk500_getsync(): not in sync: resp=0x00

Ancas:
I done it and now i have other error:
avrdude: stk500_getsync(): not in sync: resp=0x00

That's not promissing. That generally means that the IDE is not able to communicate with your aruduino.

Either, you have the wrong com port selected
OR (under the circumstances more likely)
You are shorting something out.

It could be a combination of both. If you've unplugged and plugged your arduino back in (or shorted it out for just an instant) from the com port, it may now be on a different port to the one you expect.

You might check to make sure you have the correct board selected as that will cause s sync error as well.

Also, when using the LCD_I2C library I believe you initialize it with

void setup()
{
lcd.begin(16,2);
}

Bill