C# - Microsoft.Build.Task Missing - Load Reports Into SSRS

I am trying to use .Net to load reports into SSRS. When I looked up example code they used the Warning class which, after futher research, seems to be in the Microsoft.Build.Task namespace. My problemis that this library doesn't show up when I try to reference it and when I try to add references it doesn't Microsoft.Build doesn't show in the list of .Net references. What am I doing wrong? The compiler does not recognize the class in the following: Warning[] warnings = Null;