ESS got a version bump so it plays better with R-devel (currently 2.11), which has some subtle changes to the help functions.

I’m now running the following:

The install of ESS 5.7.1 was very easy. svn checkout, and then changing some variables in Makeconf: e.g.,

## Section 1
## Installation variables for your emacs variant
##
## Variable Description
## EMACS use emacs for GNU Emacs, xemacs for XEmacs
## EMACSBATCH emacs/xemacs command for compiling elisp files
## LISPDIR Destination of compiled elisp files
## INFODIR Destination of info files
## ETCDIR Destination of script and icon files
## PREFIX(DESTDIR) Directory prepended to LISPDIR, INFODIR, DOCDIR & ETCDIR
## Specify either PREFIX or DESTDIR to over-ride /usr/local
DESTDIR=/Applications/Aquamacs.app/Contents/Resources/lisp/aquamacs/edit-modes
PREFIX=$(DESTDIR)
#
## GNU Emacs
EMACS=/Applications/Aquamacs.app/Contents/MacOS/Aquamacs
LISPDIR=$(PREFIX)/ess-mode/lisp
INFODIR=$(PREFIX)/info
ETCDIR =$(PREFIX)/ess-mode/etc

Then make and make install.