Word error pop-up when i forward certain emails

[Lefty in NY]

I've received a number of emails that, when I try to forward them the
following pop-up error message appears. Header - Microsoft Office Word.
Body - "The item could not be found"

If I copy the message into Word and attempt to send it from there, the same
pop-up appears. This happens only on certain emails and it does not matter
if they are copy only or if there is a .jpg or .gif attached or embedded.

Any ideas.