Interaction between pine and gnupg: pine sending-filters (see /etc/pine.conf) and /usr/bin/pinegpg.
gpg-encrypt and gpg-sign+encrypt -> pinegpg are called by pine as filters with the mail addresses of the recipients on the command-line. gpg is supposed to encrypt the message for these recipients.
But the filter command and pinegpg script do not call gpg correctly: there should be a -r option for each recipient, but only one is given.
Example: mail to addresses email@example.com and firstname.lastname@example.org should call gpg -at -e -r email@example.com -r firstname.lastname@example.org. Currently, the second -r is missing.
So gpg thinks the second and following addresses are filenames. The error message thus produced (something like "no such file or directory") is not easily interpreted in the context by a user who has not read the script...
This basically prevents sending encrypted mail to more than one recipient.
*** This bug has been marked as a duplicate of 21271 ***