They use samsung controller KS0066 wich is really compatible with Hitachi, in fact i have some LCD here with the same controller and i used the same code... as is and it's work...mmm weird

Yuk, probably not really handy but, worth a try...
Code:
@ __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HS_OSC_1H
@ __CONFIG _CONFIG2H, _WDT_OFF_2H & _WDTPS_128_2H
@ __CONFIG _CONFIG4L, _LVP_OFF_4L

Define OSC 10

TRISA=0
TRISB=0
Define LCD_BITS 4   ' 4-bit interface
Define LCD_LINES 2 ' 2 line LCD

' LCD should be connected as follows:
' LCD PIC
' DB4 PortA.0
' DB5 PortA.1
' DB6 PortA.2
' DB7 PortA.3
Define  LCD_DREG  PORTA
Define  LCD_DBIT  0

' RS PortA.4 (add 4.7K pullup resistor to 5 volts)
Define  LCD_RSREG  PORTA
Define  LCD_RSBIT  4

' E PortB.3
Define  LCD_EREG  PORTB
Define  LCD_EBIT  3

' RW Ground
' Vdd 5 volts
' Vss Ground
' Vo 20K potentiometer (wire wiper to Vo, adjust for contrast)
' DB0-3 No connect

Define LCD_COMMANDUS  2000 ' Adjust for slower LCD modules
Define LCD_DATAUS 50

ADCON1 = 7 ' portA digital
Pause 1000
FLAGS=0
Pause 1000 
loop: 
    Lcdout $fe, 1,"Hello"
    Pause 500 ' Wait .5 second

    Lcdout $fe, 1,"World"
    Pause 500 ' Wait .5 second

    Goto loop ' Do it forever
I heard few time, but never encouter the problem, that some LCDs are noise sensitive, what about if you add a 0.1uF and a 10uF(or higher) on the VDD line close to the LCD(as close as you can)???

Now if nothing works... it could be a blowed one... On EBay... not a surprise