If the openings book has a .ctg extension, it should be able to open in chessbase. I would just open two windows, cut the opening tree file from the CD and paste it into whatever folder I want to store my opening book. Then I could open it with whatever chess interface I want, given it recognizes the file extension - if not, I'd find a way to convert it to the file type I want looking for a help file via google. It's possible to merge openings books too with chessbase software, probably most chess softwares. Hope this helps.
You may have to open the openings book too, before you can edit it and copy to disk, as indicated in the instructions. 
Ok, this is a huge mystery. I've looked around, and can't figure it out.
I have Rybka4 installed, but the Book part is drivng me nuts.
The case it comes in says this:
Insert the Rybka4Book CD into yourCD Drive. (Done)
Start Rybka (Done)
Click on the "Openings book" tab at the top of the notation window. (Done, but it doesn't appear, only the dbase from Rybka4 does)
Now it says: To copy the Rybka4Book onto your hard disk:
Click "edit > Openings Book > Copy tree to disk"
Well, I can't for the life of me figure out how to do this last step. I don't see where "Edit" is, and of course, i can't find the other steps as well. I know someone else who cold install it, he gave me the program....
Anyone have an idea? I run Windows 7. Thanks for your time.