我正在尝试运行从Git下载的MEAN堆栈代码，但是运行npm start时出错。
我用npm install -g npm-windows-upgrade更新了我的npm，
然后我运行了npm install -g concurrently。我收到以下错误消息：
Error occured when executing command: ng build --watchError: spawn cmd.exe ENOENT
at Process.ChildProcess._handle.onexit (internal/child_process.js:229:19)
at onErrorNT (internal/child_process.js:406:16)
at process._tickCallback (internal/process/next_tick.js:63:19)
at Function.Module.runMain (internal/modules/cjs/loader.js:746:11)
at startup (internal/bootstrap/noonde.js:238:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:572:3)
Error occured when executing command: ng build --watchError: spawn cmd.exe ENOENT
at Process.ChildProcess._handle.onexit (internal/child_process.js:229:19)
at onErrorNT (internal/child_process.js:406:16)
at process._tickCallback (internal/process/next_tick.js:63:19)
at Function.Module.runMain (internal/modules/cjs/loader.js:746:11)
at startup (internal/bootstrap/node.js:238:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:572:3)