The REAL ICE frimware is NOT your application firmware. This is the code that is loaded into the REAL ICE that modifies its functionality for the project's selected device.
Open Project Properties window.
Select REAL ICE under Categories.
Select Firmware from the Options Categories combo box
Auto or manual selection of memories and ranges to program: If you check this box, you can specify which firmware image MPLAB® X IDE should load in the box below.
Click in the right-hand text box to search for a firmware file (.jam) to associate with the emulator:
MPLAB X IDE automatically downloads the correct firmware for your selected device. Only change this setting if you are having issues.