[Rd] lubridate does not install on FreeBSD any more

[Rainer Hurling]

With newest R devel

#sessionInfo()
R Under development (unstable) (2012-01-10 r58085)
Platform: amd64-portbld-freebsd10.0 (64-bit)
locale:
[1] 
de_DE.ISO8859-15/de_DE.ISO8859-15/de_DE.ISO8859-15/C/de_DE.ISO8859-15/de_DE.ISO8859-15
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

I get the following error when I try to build and install lubridate from 
sources on FreeBSD 10.0-CURRENT (amd64):

#R CMD INSTALL lubridate_0.2.6.tar.gz
* installing to library '/usr/local/lib/R/library'
* installing *source* package 'lubridate' ...
** package 'lubridate' successfully unpacked and MD5 sums checked
** R
** data
**  moving datasets to lazyload DB
** inst
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded
During startup - Warning messages:
1: Setting LC_CTYPE failed, using "C"
2: Setting LC_TIME failed, using "C"
3: Setting LC_MESSAGES failed, using "C"
4: Setting LC_PAPER failed, using "C"
Error : .onLoad failed in loadNamespace() for 'lubridate', details:
   call: utils::assignInNamespace("+.Date", add_dates, "base")
   error: locked binding of '+.Date' cannot be changed
Error: loading failed
Execution halted
ERROR: loading failed
* removing '/usr/local/lib/R/library/lubridate'
* restoring previous '/usr/local/lib/R/library/lubridate'


Do you have any idea what is going on here?

Thanks in advance,
Rainer Hurling