aFormMail script - sending mail via form

Just installed 2 forms using "aFormail" script by Alex Scott.
Release: 1.1 ($Revision: 1.6 $)
FileName $RCSfile: aformmail.php,v $

One of the forms has been emailing my client data that
is accurate, but formatted without returns. It displays correctly on
my Mac but not on his PC w/ Outlook Express. He's already set his
email to view both text and HTML, but this didn't help.
Wierd thing is, when he goes to forward or reply to this message, data becomes formatted properly with returns between each line.
Is this a bug in Outlook Express or is the glich in the PHP code?
Any help would be appreciated.
Thanks
Pete