Why is it that MikTeX's XeTeX cannot find my file?
Dude, you're right there in the same directory as the file, why can't you see it?!
Your document is inside the miktex tree. miktex will not search it there. Documents don't belong in application folders (and the miktex tree is an application folder). Put it in a documentation folder. (Addition: Depending on the concrete location of the document in the texmf tree miktex will perhaps find it if you update the FNDB, but then the next problem will be that it doesn't find the
See it as a security feature: Imagine that you try to compile inside the