Export to Excel function Not working on Server machine

i have modified my code to xml format..

                da = new SqlDataAdapter();
                conn.Open();
                da.SelectCommand = command;
                da.Fill(ds);
                ds.WriteXml("c:\\Customers.xml");

when i execute solution from the local system the data set values are copied to the xml file along with column header..then i moved the files to virtual directory under inetpub folder. through iis manager i browsed the virtual directory and run the same page , the file is getting saved in the same path but without the column header :(.. then i opened the same page from other machine through URL (thru inetrnal ip address) but the xml file is not saving to the machine.. plz help me out..

thanx n regards

T.Navin

code behind file:

    using Excel = Microsoft.Office.Interop.Excel;
    using System.Reflection;
    using System.Drawing;
    using System.ComponentModel;
    using System.Windows.Forms;

     string FilePath = ConfigurationManager.AppSettings["dataqueryfile"]
                 + "dataquery_" + DateTime.Now.ToString("yyyyMMddhhmm") ;


                Excel.Application oXL;
                Excel.Workbook oWB;
                Excel.Worksheet oSheet;
                Excel.Range oRange;

                // Start Excel and get Application object. 
                oXL = new Excel.Application();

                // Set some properties 
                oXL.Visible = true;
                oXL.DisplayAlerts = false;

                // Get a new workbook. 
                oWB = oXL.Workbooks.Add(Missing.Value);


                // Get the active sheet 
                oSheet = (Excel.Worksheet)oWB.ActiveSheet;
                oSheet.Name = "DataQuery";

                // Process the DataTable 
                DataTable dt = ds.Tables[0];

                int rowCount = 1;
                foreach (DataRow dr in dt.Rows)
                {
                    rowCount += 1;
                    for (int i = 1; i < dt.Columns.Count + 1; i++)
                    {
                        // Add the header the first time through 
                        if (rowCount == 2)
                        {
                            oSheet.Cells[1, i] = dt.Columns[i - 1].ColumnName;
                        }
                        oSheet.Cells[rowCount, i] = dr[i - 1].ToString();
                    }
                }

                // Resize the columns 
                oRange = oSheet.get_Range(oSheet.Cells[1, 1],
                              oSheet.Cells[rowCount, dt.Columns.Count]);
                oRange.EntireColumn.AutoFit();

                // Save the sheet and close 
                oSheet = null;
                oRange = null;


                oWB.SaveAs(FilePath + ".xls", Excel.XlFileFormat.xlWorkbookNormal,
                    Missing.Value, Missing.Value, Missing.Value, Missing.Value,
                    Excel.XlSaveAsAccessMode.xlExclusive,
                    Missing.Value, Missing.Value, Missing.Value,
                    Missing.Value, Missing.Value);
                oWB.Close(Missing.Value, Missing.Value, Missing.Value);
                oWB = null;
                oXL.Quit();

                // Clean up 
                // NOTE: When in release mode, this does the trick 
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();

web config file :

      <add key="dataqueryfile" value="C:\navin\"/>
      <add assembly="Microsoft.Office.Interop.Excel, Version=11.0.0.0, Culture=neutral, PublicKeyToken=71E9BCE111E9429C"/>
  <add assembly="office, Version=11.0.0.0, Culture=neutral, PublicKeyToken=71E9BCE111E9429C"/>
            <add assembly="Microsoft.Vbe.Interop, Version=11.0.0.0, Culture=neutral, PublicKeyToken=71E9BCE111E9429C"/>
            <add assembly="stdole, Version=7.0.3300.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>

plz help me out..

thanx n regards

T.Navin