In moving my mom's outlook express mail from old PC to new one (both with Windows XP), I exported from OutLook Express on the old PC harddrive to a .PST file. I have tried importing the .PST file into Outlook Express on the new PC, but it fails. I do have Outlook running on the new PC as well. The error message refers to a MAPI issue but it isn't clear to me how to fix/work around.

If Outlook isn't being used, why would you export to a pst file? Two options: Configure Outlook to use the pst file and have your Mom use Outlook instead of OE, or assuming you no longer have the original dbx files is to configure Outlook to use that pst file (while logged in with your Mom's account), then run the Import Messages Wizard in OE and select Microsoft Outlook to import from. I'd go with option 1. LIR