Your XML isn't
well-formed.
Quote:<?xml version="1.0" encoding="utf-8"?><Galaxy> <SolarSystem> <Planet id="1" Type ="Lava"> <Position x ="100" y ="0" z ="0" /> <Seed ="200" />
You probably meant <PlanetsSeed Seed ="200" />.
The current XML would make doc.LoadFile return false and doc.RootElement return 0, giving a null pointer dereference on XMLRoot->FirstChildElement("Galaxy").
You should be checking these return codes/values, namely LoadFile's result and that RootElement and FirstChildElement aren't returning null pointers!
(As an aside, style-wise typically you don't have spaces between XML attribute names and values.)
Also, I just want to restate OrangyTang's comment. You really will need a functioning debugger at some point (again), so save yourself the pain and figure out why it's not working before you really need it. Try checking your debugger's path settings.