GPG silently fails, returns blank message

What steps will reproduce the problem?
0. Assume an empty keyring
1. Add key from keyserver as normal, in this example: email@domain.com
2. Test with this command pulled from the GnuPG library: echo 'test' | sudo -u 
nobody /usr/bin/gpg --homedir /var/gpg/.gnupg --batch --yes --pgp7 
--no-secmem-warning -a -e -r email@domain.com

What is the expected output? What do you see instead?
Expectation is that 'test' becomes encrypted with the public key.
What actually happens is:
 gpg: XXXXXXXX: There is no assurance this key belongs to the named user
 gpg: [stdin]: encryption failed: unusable public key

What version of the product are you using? On what operating system?
gpg (GnuPG) 1.4.11 on Ubuntu 11.04

Please provide any additional information below.
Adding the following command-line argument in the GnuPG library fixed it for me:
--trust-model

Original issue reported on code.google.com by paul.bro...@gmail.com on 11 Feb 2012 at 1:38

goors / gpg-mailgate

GPG silently fails, returns blank message #3