Compiler doesn't recognize my DataSet

I created a DataSet object in the App_Code directory.
I then created a DataLayer.cs class in the App_Code directory.
In the DataLayer class I am using System.Data.
Yet the compiler does not recognize my DataSet. The error asks me if I am missing a directive or an assembly reference. I dont think I am because intellisense does recognize the DataSet keyword, just not the DataSet that I created. The exact code is posted below, obviously you cannot see the DataSet in the Solution Explorer but trust me, it's there. Its exact name is dsTasks.xsd and it has the attached .xss thing. Also, everything is spelled correctly. Also, I tried using  DataSet ds = new DataSet("dsTasks") but I couldn't do the fill method. Forget that anyway, what I really want to know is why it doesn't even recognize dsTasks! As far as I can tell it is there, it is spelled right, the Date Layer is referenced, the two files are even in the same directory, I have t ...