Outlook XP cannot forward or replay some emails received

[Scott Wierson]

There are some emails I receive which I cannot either
reply to or forward. I get an email responding that the
receipiant could not be reached. The email addresses are
valid. I cannot even reply to some messages sent. If I
copy the email content into a new email then I can send it
to the same recipience wihtpout any problems. Please help.

I also receive duplicates of some emails.