The applicacion sends me the next message "Method not found:
Excel._Worksheet.SaveAs (..."

I thinks that its about permissions but I do not know how to fix it.

I have the same source in two different servers, It work in one of these but
it doesn's work in the second one.

oExcel = New Excel.Application
oExcel.Visible = False : oExcel.DisplayAlerts = False
'Start a new workbook
oBooks = oExcel.Workbooks
oBooks.Open(sTemplate)
......
oSheet.SaveAs(sFile)