A new version of the mempatch.sty file is available from upstream (http://www.ctan.org/tex-archive/macros/latex/contrib/memoir/). Upstream is currently at version "2005/03/23 v3.9' while the portage version is at "2004/05/14 v2.3d".
If the Text-Markup Team doesn't mind, I can do the version bump myself...
I don't mind. Go ahead. btw, you are welcomed to join text-markup herd if you are interested in maintaining latex packages ;)
Thank you. I have added the new version to portage, but I'm currently too busy with mobile herd stuff to join yet another herd.