One suggestion: RO often has problems if not installed in the default directory of C:\Program Files\Gravity\RO
Not sure if you actually need it in the program files folder, or if the next two folders just need to be \Gravity\RO, but try reinstalling it at that location if you chose a custom one. I had this problem when I installed RO at work once, and that turned out to be the problem, the reference location of the program did not change to the new folder I installed to and was looking for C:\Program Files\Gravity\RO
Just a thought, if that doesn't work then follow Miss Pandora's advice