Often Misused: file upload error

Question

I was created site in asp.net.

In that i will upload some file using fileupload control it works fine . But at the time of security audit it gives error

as often misused file upload. Please give the solution. 

 

Code Snippet :

 

 string filename = Path.GetFileName(FileUpload1.PostedFile.FileName);

        FileUpload1.SaveAs(Server.MapPath("foldername/" + filename));

       

        con.Open();