[R] how can I use lmer on a windows machine?

[Feldman, Tracy]

To whom it may concern:

I am using R version 1.9.1 beta on a windows machine, and I am trying to
use a function called lmer (in packages lme4 and Matrix).  I am not sure
if this version will support these packages (when I install them from
the GUI, the function lmer does not work).  I wondered if I need to
install a newer version of R, and if so, which version should I install,
and how should I do that?
 
Thank you so much for your time and help.  Please send replies to
tsfeldman at noble.org

Take care,
Tracy S. Feldman

Postdoc
Noble Foundation