OK, next time post a
minimal working example and be more specific about what you mean.
I think you're referring to the fact that there is a blank page between section 1.7 and section 1.8 (the flowchart). This happens because your flowchart is too tall to fit on a page: TeX says, "this doesn't fit here" and skips to the next page. It then tries to typeset header plus image, and gets the "this doesn't fit" signal again, so it adds a page and then gets it again. It that point it gives up and gives you the overflowing-the-page output.
I'm saying this tentatively, because I don't have a copy of your document class and therefore had to try to reproduce it it with "book" by adding packages and commenting out lines.