We, the MacGPG team, are aware of a change in Jaguar that prevents GPG
from running from the command line (in a Terminal session).  This issue
also prevents certain functionality in GPGKeys - functionality that
requires a Terminal session - from working correctly. Specifically, the
path /usr/local/bin is no longer part of the default environment variables
for the system.  

Until a fix to this problem is found, it will be necessary to add
/usr/local/bin to the $PATH environment variable.  If you are running tcsh
(you'll know if you aren't - it's the default shell), you can run the
following command from Terminal to fix your system:

echo 'set path = ( $path /usr/local/bin );' >> ~/.cshrc

If you have edited your .cshrc file before, you may not want to do it this
way.  Of course, if you've edited your .cshrc before, you probably don't
even need these instructions.
