*Create the object:
oExcel = CreateObject("Excel.Application")
oExcel.Visible = .t.
*State how many worksheets will be in the xls doc via:
oExcel.SheetsInNewWorkBook = 4

*Open the doc I just made:
oExcel.Workbooks.Add()  && Here I change Your code .OPEN()
oWorkbook = oExcel.ActiveWorkbook
n = 0
FOR EACH oSh IN oWorkbook.Sheets
    oSh.Name = "Bbbb"+STR(n,1) && That is the name of the sheet
    n = n + 1
NEXT