Prevent Created With A Newer Version Message

I am running Excel 97 on one PC and 2003 on another, both need access to a workbook and both need to amend that workbook.

In my Macros I have a line in the Workbook to save etc

Workbooks("WB Name").Close SaveChanges:=True

When I run the macro on the 97 PC I get a message stating that the "file was created with a newer version of Excel Continue with save Y/N"

I have tried

Application.DisplayAlerts = False
Workbooks("WB Name").Close SaveChanges:=True
Application.DisplayAlerts = True

but the file does not save.