I am not a LeafLabs staffer.
Rev5 should work with the existing IDE.
AFAIK, all the changes on rev5 are hardware layout, silk screens etc.,and invisible to the IDE.
This OS refused to install unsigned device driver.
I believe other folks have had success at making Windows 7 do what they say, and install.
I do remember there being a problem with the Arduino IDE (which is the base of Maple's IDE) on my Mac, when it flipped to a default 64-bit app model. There is an option to run it as a 32-bit application, and everything worked.
Maybe download a version 18 Arduino IDE from http://arduino.cc/en/Main/Software
Install and run.
If there is no problem, that tells us something.
If there are problems, the messages may be found when you google, but that might tell us something too.
Sorry I can't be more help.