I think people are getting tired of responding to this one. Star Wars rebellion, aswell as its
editing programs are not made for 64 bit systems or windows vista/7. Put simply they do not work properly because the newer OS are different from older versions. There are some fixes, but generally its easiest to just download virtualbox and make a virtual system with windows xp or older installed (obviously has to be at least windows 95 to run rebellion). The reason its easier with virtualbox is because it also resolves the issues with the editing software, rather than having you fix both the game and rebed individually.
There are some other quick fixes in the following links. But usually they all end up coming back to the method i mentioned above:
Rebellion Vista x64
viewtopic.php?f=2&t=27471Rebellion in Windows 7
viewtopic.php?f=2&t=27606Edit: here are some more links regarding Reded in particular.
Editing in windows 7 (Scroll down to Thrawn888's post)
viewtopic.php?f=3&t=27854RebEd Error when trying to access Rebellion files... (essentially the predecessor to the above post)
viewtopic.php?f=3&t=27798If you scroll down the editing forum you will find several more. Aswell as a few in the questions from newbies forum.