Invalid signatures

[David Rosenstrauch <darose@xxxxxxxxxx>]

Saw these errors from pacman today, which are preventing me from 
upgrading some packages:

error: directfb: signature from "Eric Belanger <eric@xxxxxxxxxxxxx>" is 
invalid
error: xmms2: signature from "Sergej Pupykin <arch@xxxxxxxxxxxx>" is invalid
error: failed to commit transaction (invalid or corrupted package (PGP 
signature))

Anyone have an idea what's up?

DR