[Paul K]

http://support.microsoft.com/?kbid=179637 seems to the problem

Originally Posted by MS

SYMPTOMS
If you try to import messages into Outlook Express, you may receive the following error message:

Messages can not be imported from the MAPI client. An error has occurred.
If you try to export messages from Outlook Express, you may receive the following error message:

The Export could not be performed. An error occurred while initializing MAPI.
CAUSE
This behavior may occur if either of the following conditions is true:
You configure Outlook Express to be the default Simple Messaging application programming interface (MAPI) client.

-or-
You are importing mail from Outlook into Outlook Express, but you removed Outlook from your computer before you tried to import the mail into Outlook Express.
RESOLUTION
To resolve this issue, complete the methods that are described in this section in the order that they are presented.
Reinstall Outlook Temporarily
IF you are importing mail from Outlook into Outlook Express but you have already removed Outlook from your computer, reinstall Outlook and then try to import the mail again.
Change your MAPI Settings
Configure Outlook Express to not be the default Simple MAPI client before you import the mail items. To do so, follow these steps:
Restart your computer, and then start Outlook Express.
On the Tools menu, click Options.
On the General tab, click to clear the Make Outlook Express my default Simple MAPI client check box, and then click Apply.
Click OK when you receive the prompt to restart your computer.
Click OK, quit Outlook Express, and then restart your computer.

You can now import or export messages.