If the IceBox Remote control is not registering on the IceBox there are a couple of things to check.
Firstly check the batteries to ensure they are not flat. The Remote 2 (with the numeric keypad at the bottom and the blue backlight) will indicate the batteries are low when the backlight starts blinking when you press a button.
If the indicator light (the little red light between the Power and Mute buttons) blinks multiple times when you press a button on the remote control it's likely that the remote has lost it's connection to the IceBox.
You can manually force the remote to re-connect to the IceBox by unplugging the dongle from the IceBox (while the IceBox is on) then holding both the "OK" and "Back" buttons on the remote control until the red light starts flashing regularly (it will be a little slower than when the buttons are held down, and will take around 5 seconds), you can then let go of the buttons and it will keep flashing at this rate and it will be in pairing mode. At this point plug the dongle in and shortly after that the flashing will stop once it connects.