Microsoft Project - Unable to Open Project 2007 File
This document explains why you may not be able open a Microsoft Project 2007 file with an earlier version of Microsoft Project.
You receive the following message/error when attempting to open a Microsoft Project 2007 file:
"You have reached this page because the .mpp file that you are trying to open was created in Microsoft Office Project 2007. Converters for opening Microsoft Office Project 2007 files will be available during the last quarter of 2007.Until then, to open this file using Microsoft Office Project 2003, the person who created the file needs to save it to the Microsoft Project 2000 - 2003 file format."
You will need to to ask the person who sent you this file to save it to Microsoft Project 2000 - 2003 file format and send it again.
NOTE: Both 2003 and 2007 projects end with ".mpp"