The first line of the Perl script should be the shebang line. It specifies the location of the Perl interpreter. On my machine, Perl is in /usr/bin. You can find out where yours is with the command
[swithun@abednego ~]$ which perl
So, the line is
If your Perl is in one place, and the shebang line says something different, that could be why you are getting the error.
Or, the Perl interpreter is found, but your script isn't. I don't know how OS X splits the Mac side from the Unix side. Try commands like ls and pwd to work out where in the system you are from the terminal and move your Perl scripts to that location. Or, see what text editors you have access to from the terminal and do it all from there.
might help with your Active Perl installation, if the default one isn't working for you.
Don't give up.