ERROR: [4] -- Error: Unable to cast object of type 'System.DBNull' to type 'System.Byte[]'.   at isellWeb.DownloadToolKit.ProcessLinkDownloadRequest(DataAccess& oDB, HttpContext& oContext, Int32 lINstallationID, Int32 lImageID, Int32 nType)
   at isellWeb.DownloadToolKit.GetFile(HttpContext& oContext)