Ok I solved it... LOL
here is the code that made it work with the lib file LCDI2Cw at web4robot.com. I also had another issue. it seems the computer IDE cable I was using didnt pass enough current thru the small wires, I used a bigger one with thicker wires and that helped to see the screen. Backlight and contrast is working.
/*
LCDI2Cw Library - Hello World
Demonstrates the use a 16x2 LCD display.
This sketch prints "Hello World!" to the LCD
and shows the time.
The circuit:
* LCD SDA to Arduino A4 pin
* LCD SCL to Arduino A5 pin
* LCD Vdd to Arduino +5V
* LCD GND to Arduino GND
*/
// include the library code:
#include <LCDI2Cw.h>
#include <Wire.h>
unsigned char i2cAddress = 0x4C; // LCD module I2C address
// initialize the library with the number of columns and rows
LCDI2Cw lcd(20, 4, i2cAddress);
void setup() {
// LCD begin
lcd.begin();
lcd.backlight(255);
lcd.contrast(75);
// Print a message to the LCD.
lcd.print("hello, world!");
}
void loop() {
// set the cursor to line 1, column 0
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
// print the number of seconds since reset:
lcd.print(millis()/1000);
}