Line 28:                 string FolderPath = ConfigurationManager.AppSettings["FolderPath"];
Line 29:                 string FilePath = Server.MapPath(FolderPath + FileName);
Line 30: FileUpload1.SaveAs(FilePath); Line 31:                 GetExcelSheets(FilePath, Extension, "Yes");
Line 32:             }

[DirectoryNotFoundException: Could not find a part of the path 'D:\pratyusha\project\pay description\pay description\Files\bb.xls'.]
   System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) +224
   System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath) +1142
   System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy) +78
   System.IO.FileStream..ctor(String path, FileMode mode) +71
   System.Web.HttpPostedFile.SaveAs(String filename) +99
   System.Web.UI.WebControls.FileUpload.SaveAs(String filename) +23
   pay_description.autocreate.btnUpload_Click(Object sender, EventArgs e) in D:\pratyusha\project\pay description\pay description\autocreate.aspx.cs:30
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +118
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +112
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5563