R help - May 2008 - how to define .Renviron to work with different R-versions

Hi,

    I have a simple R script for printing arguments
    cat > printargs.R << EOF
    args = commandArgs()
    print(args)
    q()
    EOF

   To run this script, first I set PATH to ~/src/R-2.6.2 and execute >
R --no-save < printargs.R

   I want to run this script with different R versions by defining an
.Renviron file in the same directory as printargs.R

   cat > .Renviron << EOF
   R_VERISON=R-2.7.0
   R_HOME=~/src/${R_VERSION}
   PATH=${R_HOME}/bin:${PATH}
   R_LIBS=${R_HOME}/library
   EOF

   Now when I run > R --no-save < printargs.R, I get
   Error in gzfile(file, "rb") : cannot open the connection
   In addition: Warning message:
   In gzfile(file, "rb") :  cannot open compressed file
'/home/ppreddy/src//library/base/R/base.rdx', probable reason 'No
such
file or directory'
   Execution halted

   I do not know for sure, if I can define R_VERSION, R_HOME, and PATH
in .Renviron. All I have seen is defining R_LIBS/JAV_HOME in r-help
archives.
   So, please explain how to use the .Renviron to work with
R-different R-versions and also Should I place .Renviron in the home
dir instead of cwd?

Thanks,
Poornima.