I would have this problem from time to time in PlotMaker 3.1. Never found a solution or work around. Always had to close PlotMaker without saving. The only suggestion that worked for me was to manually save often once back in that particular file.
There is a problem with one or more of your drawings. This has come up before; you might search the archives I'm guessing about 6 months ago.
The only way to find which drawing(s) is causing the problem is to recreate the layout book and saving after each drawing. Tedious, but hopefully this will isolate the problem.
ARE you getting any error messages in ArchiCAD? This could clue you in to where the problem may stem from. Archicad can be forgiving and continue without crashing but by the time the info is saved out for plotmaker, a known memory hog, it may be too much. There may be something such as an inverted fill or slab that is problematic.
Another 'problem' originator could be an SEO.
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
"Implementing Successful Building Information Modeling"