[R] Cannot update 2.8.1 packages: unable to access index for repository...

[Marcus, Jeffrey]

I am having trouble updating packages for R 2.8.1 in Windows XP. Note that I *am* able to update packages for R 2.7.0  (see bottom of posting) so this is not an Internet proxy problem. The steps I took were to 

(a) Copy over packages from my existing (2.7.0) library subdiretory to the R 2.8.1 library subdirectory. This included  a long list of packages including RODBC, rpart,  RGraphViz, ggplot2 and their dependents. 
(b) From within Rgui, run  update.packages(ask='graphics')

I tried this several times with different repositories and mirrors and each time got messages like:

Warning: unable to access index for repository http://streaming.stat.iastate.edu/CRAN/bin/windows/contrib/2.8
Warning: unable to access index for repository http://www.stats.ox.ac.uk/pub/RWin/bin/windows/contrib/2.
Warning: unable to access index for repository http://www.omegahat.org/R/bin/windows/contrib/2.8
Warning: unable to access index for repository http://cran.fhcrc.org/bin/windows/contrib/2.8


Finally, I noticed that a recent R-help thread http://www.nabble.com/Installing-the-Rstem-package-td22357873.html#a22362058

Includes the following comment (excerpted) from Professor Brian Ripley

     a) There seem to be no Windows binaries on Omegahat for R > 2.7. 

     b) A few are available from CRAN extras (one of the default 
         repositories on Window), and I've added Rstem.  So please try again 
         now.

Does this mean that I should update 2.8.0 libraries from zip files manually? Or is there a more convenient workaround for updating? 

By the way, here is what I see with R 2.7.0

> update.packages(ask='graphics')
trying URL 'http://streaming.stat.iastate.edu/CRAN/bin/windows/contrib/2.7/RODBC_1.2-4.zip'
Content type 'application/zip' length 195082 bytes (190 Kb)
opened URL
downloaded 190 Kb

package 'RODBC' successfully unpacked and MD5 sums checked
Warning: cannot remove prior installation of package 'RODBC'

The downloaded packages are in
        C:\Documents and Settings\jmarcus\Local Settings\Temp\Rtmp5QBblK\downloaded_packages
updating HTML package descriptions

Thanks for any help
____________________________________________
JEFF MARCUS
Manager, Applied Data Analysis

NUANCE COMMUNICATIONS, INC.
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