The Child Exited 127 Mystery

[Bill <tfc4@xxxxxxxxxx>]

The scene of the crime:

Each time Mutt mail is sent an error appears:

"Child Exited 127"


The clues:

#1. The mail IS delivered, but the window with the e-mail remains
    open. And this cryptic message appears:

"Error sending message, child exited 127 (Exec error.)."


#2. Since the window with the e-mail remains open, 'q' is pressed to
    dismiss it, producing this message:

"Postpone this message? ([yes]/no):"


#3. After the email window is finally closed with 'no', Mutt returns
    another message:

"Mail not sent."

But, in fact, the mail HAS been sent, and Mutt has even posted it in
the 'sent' mailbox.

Any leads pointing to perpetrator of this crime will be appreciated.

bj