Qt Creator Error 258 - windows

Question

I'm trying to use Qt Creator for the first time, but I can't manage to get Hello World running. This is what my kit looks like:
Name: MyKit
File system name: MyKitFileSystemName
Device type: Desktop
Device: Local PC
Sysroot: (blank)
Compiler: (long path leading to mingw32\bin\g++.exe)
Environment: No changes.
Debugger: (long path leading to mingw32\bin\gdb.exe)
Qt version: 5.7.0 MSVC2015 64bit
Qt mkspec: (blank)
CMake Tool: (long path leading to cmake\bin\cmake.exe)
CMake Generator: CodeBlocks - MinGW Maketiles
CMake Configuration: (left this as default)
There are some things I should note about the kit. If I use an auto-detected kit, I can't select my compiler. There's also a red octagon next to the kit, I'm not really sure what that means.
When I try to run the Hello World program(from https://wiki.qt.io/Qt_for_Beginners), I get the following issue:
[debug] Error 258
And here's the output:
15:08:56: Running steps for project myProject...
15:08:56: Configuration unchanged, skipping qmake step.
15:08:56: Starting: "C:\Program Files (x86)\mingw-w64\i686-5.3.0-posix-dwarf-rt_v4-rev0\mingw32\bin\mingw32-make.exe"
C:/Program Files (x86)/mingw-w64/i686-5.3.0-posix-dwarf-rt_v4-rev0/mingw32/bin/mingw32-make -f Makefile.Debug
/usr/bin/sh: -c: line 0: syntax error near unexpected token `('
/usr/bin/sh: -c: line 0: `C:/Program Files (x86)/mingw-w64/i686-5.3.0-posix-dwarf-rt_v4-rev0/mingw32/bin/mingw32-make -f Makefile.Debug'
Makefile:34: recipe for target 'debug' failed
mingw32-make: *** [debug] Error 258
15:08:58: The process "C:\Program Files (x86)\mingw-w64\i686-5.3.0-posix-dwarf-rt_v4-rev0\mingw32\bin\mingw32-make.exe" exited with code 2.
Error while building/deploying project myProject (kit: MyKit)
When executing step "Make"
After a quick search, I found this piece of advice: "remove c:/Program Files (x86)/Git/bin from %PATH% environment variable, and make sure QT installation and your project directory not locate at any directory with space or any special characters".
Git was not in my PATH, and there were no spaces or special characters in the QT installation directory or project directory(although there are spaces in the compiler's path).
What am I doing wrong? My best guess is that it's a problem with the compiler. The path has both "mingw-w64" and "mingw32" so I'm not really sure if it's 32-bit or 64-bit. I'm guessing that it would not work if it was 32-bit.
I hope that I'm missing something obvious so that this can be easily resolved!