Error occur when export reports

Hi all,

We have issues when  exporting the file to excel from the window Inventory Part – Order Point. we cannot generate the excel file  when click  RMB and choose export report – standard. then there is a error shows Application not found . you can see full error below. its not works only for two users.working fine for others .

Error  Details

Ifs.Fnd.FndSystemException: Explorer: An Unhandled Exception has occurred ---> System.ComponentModel.Win32Exception: Application not found
   at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)
   at System.Diagnostics.Process.Start()
   at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)
   at Ifs.Application.Invpla_.frmInventoryPartInvplaInfo.OpenSpreadsheet(String spreadsheet)
   at Ifs.Application.Invpla_.frmInventoryPartInvplaInfo.cmdExportReport_Execute(Object sender, FndCommandExecuteEventArgs e)
   at Ifs.Fnd.Windows.Forms.FndCommand.OnExecute(Component component)
   at Ifs.Fnd.Windows.Forms.FndContextMenuStrip.ExecuteCommand(ToolStripMenuItem menuItem, EventArgs e)
   at Ifs.Fnd.ApplicationForms.FndContextMenuStripInternal.ExecuteCommand(ToolStripMenuItem menuItem, EventArgs e)
   at Ifs.Fnd.Windows.Forms.FndToolStripMenuItem.OnClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
   at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ToolStrip.WndProc(Message& m)
   at System.Windows.Forms.ToolStripDropDown.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   --- End of inner exception stack trace ---

Is anyone know what the problem with this is?can you kindly help.

Thank You 

Sara