On explorer16 board have 4 footprint for connect any type of LCD. And I think I use LCD with correct footprint on board.
Power supply to LCD is 5V already.
I worry that the problem is come from code. but I don't know where is it?
Draw circuit in Proteus, run your code. If not works than post your circuit and your code; maybe we can help.
Actually you can go to "C:\Program Files\Labcenter Electronics\Proteus 7 Professional\SAMPLES\VSM MPLAB Viewer\Eval Boards\Explorer16 with PIC24FJ128GA010"
and use this Explorer16 SCH.