R devel - Dec 2011 - paste0 bug in install.packages() - leopard installer?

Hello,

I get the following:
> install.packages("abind",
repos="http://cran.fhcrc.org", type="source")
trying URL 'http://cran.fhcrc.org/src/contrib/abind_1.4-0.tar.gz'
Content type 'application/x-gzip' length 19642 bytes (19 Kb)
opened URL
=================================================downloaded 19 Kb

* installing *source* package 'abind' ...
** package 'abind' successfully unpacked and MD5 sums checked
** R
** preparing package for lazy loading
** help
*** installing help indices
** building package indices ...
** testing if installed package can be loaded
*** arch - i386
*** arch - ppc
Error in paste0("(^|[^%])(%%)*%", spec) : not a BUILTIN function
Calls: Sys.setenv -> .expand_R_libs_env_var -> expand -> gsub ->
paste0
Execution halted
*** arch - x86_64
ERROR: loading failed for 'ppc'
* removing
'/Library/Frameworks/R.framework/Versions/2.15/Resources/library/abind'

The downloaded packages are in
	'/private/tmp/RtmpiZoTMy/downloaded_packages'
Warning message:
In install.packages("abind", repos =
"http://cran.fhcrc.org", type = "source") :
  installation of package 'abind' had non-zero exit status

This is with a clean install of the R-devel package installer from
http://r.research.att.com (sessionInfo() below).  It only seems to be
triggered by the type="source" flag.
I think the problem may be with the installer, as this problem does
not occur with the same revision of R-devel built from source on the
same machine.
Incidentally, this problem doesn't occur with R-devel installed via
the installer on a Lion machine but does occur on two different
Leopard machines.

sessionInfo()
R Under development (unstable) (2011-12-12 r57875)
Platform: i386-apple-darwin9.8.0/i386 (32-bit)

locale:
[1] C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] tools_2.15.0

Thanks,
Dan