R interpreter not recognized

I am trying to install a program based on R, but I am receiving the
following error message:
root at darkstar:/home/maria/UCS# perl System/Install.perl
Error: Can't run the R interpreter (/usr/local/bin/R).
Please make sure that R is installed and specify the fully qualified
filename of the R interpreter with -R if necessary (see "doc/install.txt").

I do have installed R, and I can see it (it is working also fine when I use it):

which R
/usr/local/bin/R

I have specified the location of the R interpreter with -R (or -rh)
/usr/local/bin/R" when running the program, but it still doesn't work.
I have also used -R /usr/local/lib/R/bin/R or -rh
/usr/local/lib/R/bin/R.
I have also added the locations to my search path.

It seems that the problem comes from my environment, but I cannot
figure out what's wrong. Do you have any clues why the interpreter
cannot be found?