title: Angular cli (404 Not Found) loading http://localhost:4200/symbol-observable
body: <p>Problem appears after angular cli update to beta 9:</p>
  
  <pre><code>Failed to load resource: the server responded with a status of 404 (Not Found)
  zone.js:461 Unhandled Promise rejection: (SystemJS) Error: XHR error (404 Not Found) loading http://localhost:4200/symbol-observable
          at XMLHttpRequest.wrapFn [as _onreadystatechange] (http://localhost:4200/vendor/zone.js/dist/zone.js:769:30)
          at ZoneDelegate.invokeTask (http://localhost:4200/vendor/zone.js/dist/zone.js:356:38)
          at Zone.runTask (http://localhost:4200/vendor/zone.js/dist/zone.js:256:48)
          at XMLHttpRequest.ZoneTask.invoke (http://localhost:4200/vendor/zone.js/dist/zone.js:423:34)
      Error loading http://localhost:4200/symbol-observable as "symbol-observable" from http://localhost:4200/vendor/rxjs/Observable.js ; Zone: &lt;root&gt; ; Task: Promise.then ; Value: Error: (SystemJS) Error: XHR error (404 Not Found) loading http://localhost:4200/symbol-observable(…)consoleError @ zone.js:461
  zone.js:463 Error: Uncaught (in promise): Error: (SystemJS) Error: XHR error (404 Not Found) loading http://localhost:4200/symbol-observable(…)consoleError @ zone.js:463
  http://localhost:4200/symbol-observable Failed to load resource: the server responded with a status of 404 (Not Found)
  </code></pre>
  
  <p>My <a href="http://wklej.org/id/2702741/" rel="nofollow">package.json</a> already installed. Updated to latest.
  XHR like errors and answers does'nt solve it.
  How can I solve this problem.</p>