Found a solution at the appended address, see there for reference.

Thanks Ted and DeGuess for your replies.

Wolfgang.

======= A S O L U T I O N =========
http://forums.techguy.org/windows-95...-exe-open.html
as follows:

Join Date: Nov 2003
Location: New Orleans, Louisiana
Experience: MCSE, MCSA, MCP, CET

If you are using Outlook Express for your email now, read the
following.

Open My Computer and navigate to: Tools/Folder Options/File Types tab.
Scroll down to the file extension "EML" and select it. What does it say

in the Details section about the file type and what program it opens
with?
If it has something like "EarthLink Mail Message" or "Opens with blank

space then continue.

Click the Advanced button. In the Actions box, click Open and then
click the
Edit button.
In the "Application used to perform action" box replace the text there
with
the following:

"C:\Program Files\Outlook Express\msimn.exe" /eml:%1

(Enter this text 'exactly' as shown, including the quotes, the space
between
" and / and the colon.)

Select the Use DDE check box.
In the "Application" box type: msimn
In the "Topic" box type: system
Leave the other boxes blank and press OK/OK/Apply/Close.

Exit everything and reboot the computer.