Comment 5 for bug 179640

It's interesting that the error says value "-99". This makes me wonder if perhaps there is a preference setting or something? Could it be something in your ~/.inkscape/ preferences?

It also mentions floatx. I see that this value is used in libgdl/gdl-dock-item.c and gdl-dock.c. I wonder if perhaps you had the dock open to a particular dialog when the crash occurred?