This 'How-To' document pertains to emails where you can not open the 'djvu' attachment. Below is How-To correct this problem for users of Outlook Express. Other e-mail programs may have similar options, however the steps below are for Outlook Express ONLY.
Open Outlook Express
Select Tools and then Options...
Click on the 'Security' Tab and un-check the option circled below.
Click on the 'Apply' button and then the 'OK' button.
Close or Exit out of Outlook Express
Double Click on the Outlook Express icon to re-open it. Your attachments should now be there.