I apologize for the delay in my reply. Here is what worked:
- open Excel 2007 set macro security to "disable with notification"
and remove current folder if already a trusted location
- save the file as .xls
- when the .xls file is opened there is a notification that some
content has been disabled
- click the button to enable, open the trust center, trust the
location... and it works

It doesn't address the root problem (why Excel 2007 is not executing
Workbook_Open code) but is a workaround.

Thanks,
SMc