In order to import OE4 messages they must be located on a local hard drive in a sub-folder named Mail and must not have the Read Only attribute set. (This is commonly set if they were backed up on a CD.)
Make sure that the MBX/IDX file pairs are there along with Folders.nch. Then use File | Import | Messages | Microsoft Outlook Express 4 and point to the folder that holds the /Mail sub-folder, not to the /Mail sub-folder itself or the data files.
If you cannot get this to work, use this tool to extract the messages as *.eml files and then drag the messages back in to an OE folder:
MBXtract: http://chattanooga.net/~scochran/MBXtract.htm
visitors to this page since 6 OCT 00
Copyright 2000, 2001 Frank Saunders
Last Updated 14 NOV 01