First, try getting a new copy of NoteBook. Your download may have been corrupted somehow. You can get a copy here:

http://www.circusponies.com/downloads

If that doesn’t make a difference, what kinds of software have you installed or other changes have you made in that time frame? Try disabling those things and see if that helps.

Do you have any haxies (third party OS X extensions typically not authorized by Apple) installed? These are notorious for causing problems and not just with NoteBook.

Failing that, it’s then best to contact Support here.

I am having a similar problem.
I have notebook 3.0 (I re-downloaded it to be sure). Specifically, when I try to “drag & drop” a PDF file of any size, the program immediately quits and I get a message saying that: “The Application Notebook quit unexpectedly.”
I can still open a notebook and add text, but the main value to me is the ability to save PDF files. I sent a help request to support a few days ago but have not heard back from them yet.

Additional Info:
I have not yet heard from my previous email so I have done some trial & error.

When I reinstalled vers 2, the problem went away (ie. I could add PDF’s no problem without it crashing the program.)

Is this a bug with vers 3?

Is MacJournal more stable?