10000 : Problem with GTP.NET Gantt placed on a tab:

Problem with GTP.NET Gantt placed on a tab:


Dear Sir, I get this error when using the gantt control. Any idea?
See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.
************** Exception Text **************
System.IndexOutOfRangeException: Index -1 is not non-negative and below total rows count.
   at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
   at System.Windows.Forms.Control.set_Visible(Boolean value)
   at System.Windows.Forms.TabPage.set_Visible(Boolean value)
   at System.Windows.Forms.TabControl.UpdateTabSelection(Boolean uiselected)
   at System.Windows.Forms.TabControl.OnSelectedIndexChanged(EventArgs e)
   at System.Windows.Forms.TabControl.WmSelChange(Message& m)
   at System.Windows.Forms.TabControl.WndProc(Message& m)
   at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

We are running .NET 1.1.4322 SP1, same as you?
It works perfectly with sp1 of dotnet framework