Visual Studio 2015：目标wwwroot / css / site.css未写入，因为未找到源文件。

I'm trying to use grunt in my ASP project, but for whatever reasons have get a stupid warning-message from Visual Studio. How you can see down, the bower-task has been executed, but haven't uglify- and less-tasks. Gruntfile.js and folder "wwwroot" are in the same folder. What's wrong ?I'm trying to use grunt in my ASP project, but