[Evolution] "keyring key is unusable" "no user or host name"

["Matt Price" <moptop99 gmail com>]

hi,

i've been trying to track down what seemed like a bug in evolutin,
where some messages wouldn't display when called up -- it seemed as
though evolutin were hanging on the display.  it turns out that most
of the time, the messages were gpg-signed, and in fact, most often it
was messages from me myuself.  So I uninstalled all gpg-agents
(seahorse, gnupg-agent, gnome-gpg) one by one; this didn't resolve my
problem but did give me an error from withing evolution:

 e-data-server-ui-WARNING **: Keyring key is unusable: no user or host name

i wondered whether anyone could tell me what that means and what i
might do to resolve it (e.g. do i need to run gpg from the command
line to fix my keyring or something)?

anyway i'm eager to fix this, so as always i appreciate any help.  thanks,

matt