Requirements
To use this plugin you need the following pieces of software (see the documentation for each package)
- QGIS 1.x
- Python 2.5
- R version <=2.8.1
- R packages rgdal and adehabitat, with all their dependencies (use 'dep = TRUE' when installing)
- RPy2, packaged for most distributions, including Debian (and Ubuntu), Windows, MacOSX

Windows users can download ALL THIS SOFTWARE via OSGeo4W installer, excluding R packages. This ensures compatibility.
Linux users can cope with the packages provided by each distribution.

As a uninterested advice, please DO NOT UPDATE PACKAGES SEPARATELY. it can break communication among them, and force you to first individuate the source of errors, then crawl the web to be able to downgrade, or struggle until all other sotware upgrades too.