Did you sign the correct file? After a `summon -d` I still get:
Found source file doxygen-1.5.0.src.tar.gz for spell doxygen in
/var/spool/sorcery
Waiting for any Solo casts to complete...
Waiting for any other casts of doxygen to complete... done.
Building doxygen
GPG checking source file doxygen-1.5.0.src.tar.gz...
gpg: Signature made Tue Oct 17 04:02:24 2006 PDT using RSA key ID AF8857ED
gpg: BAD signature from "Flavien Bridault (Source Mage GNU/Linux GPG
Signing Key) <vlaaad AT sourcemage.org>"
gpg: binary signature, digest algorithm SHA512
Failure to verify gpg signature
Abort? [y]