This topic is discussed here: Can not compile: arm-none-eabi-g++: command not found - #8 by maxgerhardt
The problem lies that the 3rd-party platform you’re using attempts to use a Linux 64-bit compiler for your Windows system, which of course doesn’t work. As a first fix, you should force the usage of a compiler for Windows by adding:
platform_packages = toolchain-gccarmnoneeabi@http://dl.platformio.org/packages/toolchain-gccarmnoneeabi-windows_x86-1.80201.190214.tar.gz
in the environment you’re compiling for in the platformio.ini.