What do you mean "receive them"?
Do you have installed the Adobe Reader? See
www.adobe.com.
Are you trying to access them on a web site with a web browser and it
fails? I'm assuming that installed Adobe will fix this. But if not,
then check with the support FAQ on Adobe's web site for clues. It's
their product. You don't give enough details for any furhter debugging
here.
Are you trying to read attachments in Outlook Express or some other
email client and you are blocked? If yes, it could be you have
configured Outlook Express to blocking reading of attachments. Change
in Menu: Tools/Options/ Tab: Security.
Hope this is useful to you. Let us know.
rms