Note also that to use the R-in-Perl mechanism one must have built R as a shared library. (This is not necessary when calling Perl from R.) You can check if this has been done by checking to see if libR is in the directory $R_HOME/lib/. If this is not there, you are advised to clean the entire R distribution (with make distclean) so as to start from scratch and then configure and compile R using the --enable-R-shlib to R's configuration script.