assuming you have pgp installed, it looks like i need to rebuild mpgp for the new pgp components; i will try to do it this weekend.
however, i should say that mpgp is not used much by people, just because it requires pgp and is complicated to use.
overwhelmingly, people use instead the mcpsfish addon for exchanging keys.
its installed by default when you install mircryption, you just have to load it via the instructions in the readme:
STEP 3D: If you want to install the 3rd party fish key exchange addon
(recommended), type: /load -rs mircryption/mcpsFishDH.mrc"