WINDEV workbook class problem (no replies)

Hi,
I've one code:
xls>>Workbooks>>Open(NomFichierSel)
xls>>Sheets>>Item( 1 )>>Name="Commandes"
xls>>WorkSheets>>Add()
xls>>Sheets>>Item( 1 )>>Name="Caractéristiques"
xls>>ActiveWorkbook>>Save

This code is giving the following error:

Error at line 29 of Click Btn_ExportExcel process.
'Open' Automation method called.
Attempt to invoke <Open> method or to read <Open> property. Error returned by Automation/ActiveX object:
'Erreur 800A03EC : Office has detected a problem with this file. To help protect your computer this file cannot be opened.'
Attempt to invoke <Open> method. Error returned by Automation/ActiveX object:
'Erreur 800A03EC : Office has detected a problem with this file. To help protect your computer this file cannot be opened.'
Attempt to read <Open> property. Error returned by Automation/ActiveX object:
'Erreur 800A03EC : Office has detected a problem with this file. To help protect your computer this file cannot be opened.'
Attempt to write <Open> property. Error returned by Automation/ActiveX object:
'Erreur 800A03EC : Unable to set the Open property of the Workbooks class'

What maybe the reason for this error?
How to resolve it?