Hi again,

Unfortunately it doesn't -- the check you initially pointed out in Graph/Makefile.PL still fails:

# Some Debian distributions have a broken List::Util (see rt.cpan.org 
+#9568)
eval 'require Scalar::Util; import Scalar::Util qw(weaken)';
if ($@) {
    die <<__EOF__;
$@
You do not have Scalar::Util::weaken, cannot continue, aborting.
__EOF__
}
[download]

It doesn't appear I have an "extra" version of Scalar::Util anywhere, either:

./lib/5.8.7/aix/auto/List/Util/Util.so
./lib/5.8.7/aix/auto/List/Util/Util.bs
./lib/5.8.7/aix/List/Util.pm
./lib/5.8.7/aix/Scalar/Util.pm
./lib/5.8.7/CGI/Util.pm
./lib/5.8.7/Hash/Util.pm
./lib/site_perl/5.8.7/HTTP/Headers/Util.pm
./lib/site_perl/5.8.7/Data/Stag/Util.pm
./lib/site_perl/5.8.7/Bio/Graphics/Util.pm
./lib/site_perl/5.8.7/Crypt/DSA/Util.pm
./lib/site_perl/5.8.7/Crypt/OpenPGP/Util.pm
[download]

It appears that the xs is getting installed okay, but is not being exported and so weaken() appears in @EXPORT_FAIL. I'm willing to put in more time trying to debug this, but I don't even have a clue where to start on seeing why the export fails. Any pointers on where to start looking?

I'd suggest filing a bug report with rt.cpan.org, to see if that generates some further ideas.

Done -- many thanks for your perseverance & help. I learned a few new tricks seeing how you debugged it.