I've tried to edit the CMX opening book to build a stronger one but I'm unable to load it and the application is closed!Why?
I have also noticed that I can import Winboard engines into CM but in the same time I'm not able to edit their rating or to write some infos about their style and their history!Why?
Hope you could solve these problems

That's odd... I'm able to able to edit the CMX opening book.

From the Main Menu, I went to Learn -> Openings -> Opening Book Editor , and then selected CMX.obk. Is that how you're doing things?

Not being able to enter comments about a Winboard engine isn't really a bug, it's more of an omission. My guess is that the developers didn't consider that anyone would want this capability...

I was able to solve the first problem thanks to the last patch...but the second problem remain

Well, like I said, your second issue isn't really a bug... it just wasn't designed to let you enter comments about a Winboard engine.

I do agree that it would be a nice feature to have.