You have copied and pasted the .pm module without the associated binary files. To do a complete local install of rrdtool you would:

$ wget http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/pub/rrdtool.
+tar.gz
$ tar xzf rrdtool.tar.gz
$ cd rrdtool-1.0.49/
$ sh configure --prefix=/home/neteng/rrdtool
$ make && make install

$ cd /home/neteng
$ cat test.pl
#!/usr/bin/perl
use lib '/home/neteng/rrdtool/lib/perl';
use RRDs;
print $RRDs::VERSION, $/;

$ ./test.pl
1.000491
[download]

cheers

tachyon