[R] Unable to install packages on Mac OS X

[Miguel Leal]

I'm having problems installing packages.

I'm working on the R version 2.13.1 in a Mac OS X version 10.6.8.

I'm not able to search or install packages. For instance, I have the following error message:

> install.packages("lattice")
Warning: unable to access index for repository http://cran.pt.r-project.org/bin/macosx/leopard/contrib/2.13
Warning message:
In getDependencies(pkgs, dependencies, available, lib) :
  package 'lattice' is not available (for R version 2.13.1)

Thank you in advance
Miguel