$ perl -w Makefile.PL
Checking if your kit is complete...
Looks good
Writing Makefile for Graph
Weak references are not implemented in the version of perl at (eval 13) line 1

You do not have Scalar::Util::weaken, cannot continue, aborting.
# Looks like your test died before it could output anything.

##</code><code>##

$ perl -MCPAN -e shell

cpan shell -- CPAN exploration and modules installation (v1.8)
ReadLine support enabled

cpan>
cpan> install Scalar::Util
CPAN: Storable loaded ok
Going to read /db2/dlink/.cpan/Metadata
  Database was generated on Tue, 13 Dec 2005 01:06:49 GMT
Scalar::Util is up to date.

##</code><code>##

$ perl -MScalar::Util -e 'print $Scalar::Util::VERSION'
1.18

##</code><code>##

$ perl -v

This is perl, v5.8.7 built for aix

Copyright 1987-2005, Larry Wall

Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.

Complete documentation for Perl, including FAQ lists, should be found on
this system using `man perl' or `perldoc perl'.  If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.

$ oslevel
5.2.0.0