Nested messages (*.EML files) is a common problem when messages come from AOL, WebTV or
Netscape.  Some mail programs, such as AOL, always do a Forward as Attachment.  Netscape
does this by default, but the sender can do a "Forward Quoted" instead to avoid the
problem.

Often the attachment includes "Content-Disposition: inline".  Some mail programs honor
this.  Unfortunately OE doesn't.  With the exception of images (which is controlled by
Tools, Options, Read in OE4 or a registry setting in OE5), OE will not display attachments
Inline.  Instead you have to open each attachment.  If a message has been forward 10 times
you need to go down 10 levels of opening attachments.

If they are simple text messages, a quick workaround is to look at the Message Source
(Ctrl-F3).