OK, tracked down the bug, I think. I have no idea why this would be Win10-specific. The problem is that FeMonitor derives from FePresentableParent, which is currently being defined in Squirrel. This causes type lookups to go a bit, uh, squirrely. (heh)
The fix appears to be changing fe_vm.cpp to look something like this:
fe.Bind(_SC("PresentableParent"),
Class<FePresentableParent, NoConstructor>()
.Overload<FeImage * (FePresentableParent::*)(const char *, int, int, int, int)>(_SC("add_image"), &FePresentableParent::add_image)
.Overload<FeImage * (FePresentableParent::*)(const char *, int, int)>(_SC("add_image"), &FePresentableParent::add_image)
.Overload<FeImage * (FePresentableParent::*)(const char *)>(_SC("add_image"), &FePresentableParent::add_image)
.Overload<FeImage * (FePresentableParent::*)(const char *, int, int, int, int)>(_SC("add_artwork"), &FePresentableParent::add_artwork)
.Overload<FeImage * (FePresentableParent::*)(const char *, int, int)>(_SC("add_artwork"), &FePresentableParent::add_artwork)
.Overload<FeImage * (FePresentableParent::*)(const char *)>(_SC("add_artwork"), &FePresentableParent::add_artwork)
.Func(_SC("add_clone"), &FePresentableParent::add_clone)
.Func(_SC("add_text"), &FePresentableParent::add_text)
.Func(_SC("add_listbox"), &FePresentableParent::add_listbox)
.Func(_SC("add_surface"), &FePresentableParent::add_surface)
);
fe.Bind( _SC("Monitor"),
DerivedClass <FeMonitor, FePresentableParent, NoConstructor>()
.Prop( _SC("num"), &FeMonitor::get_num )
.Prop( _SC("width"), &FeMonitor::get_width )
.Prop( _SC("height"), &FeMonitor::get_height )
);