Signing outgoing emails using GPG in mutt: "Permission Denied?"

I'm having the timiest of times getting the mutt email client to sign outgoing emails with my GPG key. Here's my .muttrc currently, as suggested here:

Code:set crypt_use_gpgme=yes
set postpone_encrypt = yes
set pgp_self_encrypt = yes
set crypt_use_pka = no
set crypt_autosign = no
set crypt_autoencrypt = no
set crypt_autopgp = yes
set pgp_sign_as=0xblahblahblahEventually I'd like to have autosign on, but for now I hit 'p', then 's' to sign with the key specified above. I keep getting the following error after hitting 'y' to send:

Code:error signing data: Permission denied?Google gives me nothing when I quote this message.

I've got gpg-agent and pinentry installed. Working in an ssh session (not trying to tunnel or anything like that). Running mutt as root. Root attained via "su -" from a standard user. No X server running. I've tried several things:

environment variables

• export GPG_TTY=$(tty)
• export GPG_AGENT_INFO=~/.gnupg/S.gpg-agent

.gnupg/gpg-agent.conf options (of varying combinations):

• pinentry-program /usr/bin/pinentry
• allow-loopback-pinentry
• use-standard-socket
• enable-ssh-support

My best hunch at the moment is some permissions quirk of using "su -", but that's just where I'm at now. I've tried running mutt as a regular user (with its own generated GPG key) to no avail, still the same "Permission denied?" message after trying to send. Makes me worried it could be some missing package. Could use some help on this one! :banghead: