Self.navigationController?.pushViewController fails screen transition when using Swift Library PageMenu

Xcode 6.4, Swift is developing an ios app.

I am using Swift's library "PageMenu".
NextView without FirstView→ PegeMenu using PageMenu
Unable to transition to

UIButton is installed in FirstView and
when tap action is performed self.navigationController?pushViewController(NextView(), animated:true)
So, I want to transition, but nothing happens when I tap the button.

varmodalView=UINavigationController (rootViewController:NextView())
modalView.modalTransitionStyle=UIModalTransitionStyle.CoverVertical
self.presentViewController(modalView, animated:true, completion:nil)

If so, you can transition to modal, but if it is modal, you can transition to NextView
self.dismissViewControllerAnimated (true, completion:nil)
When you close the modal in , the PegeMenu tab bar installed in FirstView hides behind the NavigationBar.(Normal: PageMenu tab under NavigationBar)

Is there any solution?
Thank you for your cooperation.