Excel 2007 workbook_open events are not working

Hi,
I have my lab computer upgraded from Excel 2003 to Excel 2007. Follwing code is not working on this computer.

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
ThisWorkbook.Worksheets("summary").Range("d5") = Environ$("username")
ThisWorkbook.Worksheets("summary").Range("d6") = Now()
End Sub

Private Sub Workbook_open()
ThisWorkbook.Worksheets("summary").Range("d7") = Environ$("username")
ThisWorkbook.Worksheets("summary").Range("d8") = Now()
End Sub

The error is "Run Time Error 57121 Application defined or Object defined error'
My new Laptop has Excel 2007 insatlled by default( I mean not upgraded from Excel 2003) and the above code works well. Any idea what is happening?