Some days ago I experienced weird problem with my Enigmail in Icedove e-mail client. When I tried send signed or encrypted message I saw the following error message:
“GnuPG reported an error in the communication with gpg-agent (a component of GnuPG).”
Problem is caused by compatibility issues betwwen GnuPG and Enigmail plugin.
The easiest way to manage with this problem is installing dedicated version of Enigmail from your distro’s repository.
First of all uninstall Enigmail plugin from Icedove (Tools->Addons->Enigmail->Disable, next press Uninstall button).
Next install Enigmail package.
# apt-get install enigmail
This version is fully compatible. This is the easiest way to run Enigmail again. Good luck!