Look at Outlook Express's settings at Tools, Options, Security. You may have set it to block that attachment.
You can always just save it to the drive and then open it.
I had an email sent to me by a secure source and in place of where the attachment is supposed to be, it says, outlook express has denied access to the attachment. I know that this is a safe email so how will I be able to view the attachment. Win98se. I.E. 6sp1 using Norton anti virus. Thanks, John