Failure to compile c++ for WebGL

Hello!

I'm trying to build a simple text adventure game in Unity 5.4.1f1. The game builds with no problem for Windows, but when I attempt to build it for HTML5, it fails. It hangs on "Converting managed assemblies to C++ for several seconds, and then pops up with two errors. A screenshot is attached, though may prove unhelpful. I have tried installing emscripten directly, as a post on another forum made me think that may be the source of the issue, but the problem persists. The stack trace is... large, but I think the relevant portion is this:

 Unhandled Exception: Unity.IL2CPP.Building.BuilderFailedException: WARNING  root: -I or -L of an absolute path "-IC:\Users\Susurus Mortis\Desktop\Continuing Education\Udemy\Unity\Escape from Spider's Cleft\Temp\StagingArea\Data\Native\UserAssembly.bc" encountered. If this is to a local system header/library, it may cause problems (local system files make sense for compiling natively on your system, but not necessarily to JavaScript). Pass '-Wno-warn-absolute-paths' to emcc to hide this warning.
 ERROR    root: compiler frontend failed to generate LLVM bitcode, halting