I am sorry, I have no idea. It looks like you have some connection errors. For me, wget 'ftp://ftp.perl.org/pub/CPAN/authors/01mailrc.txt.gz' works fine.

Note: most likely you will also have to install the gnuplot package for your system. Either with the system package manager, for example dnf, apt-get, etc., if it's some Linux or download the source from https://sourceforge.net/projects/gnuplot/files/gnuplot/ and compile&install or download a binary dist from http://www.gnuplot.info/download.html