I have following package.json configuration
\"dependencies\": { \"@angular/common\": \"2.2.1\", \"@angular/compiler\": \"2.2.1\", \"@angular/core\": \"2.2.1\", \
mkishorem is right.
I also got same error and fix with adding override code at package.json like below
"devDependencies": { "extract-text-webpack-plugin": "2.0.0-beta.5" }
no need to downgrading to angular-cli all.