I just wanted to add that, as recommended here:

http://sial.org/howto/perl/life-with-cpan/macosx/

at some point I did this:

cpan> o conf makepl_arg "INSTALLBIN=/usr/local/bin INSTALLSCRIPT=/usr/
+local/bin"

cpan> o conf commit
[download]

Is that what's causing the problems?

At that link it also says:

The first time CPAN is invoked, it will run through a set of questions, such as which CPAN mirror site to use. Following the questions, CPAN may recommend that you install Bundle::CPAN or Bundle::libnet. Avoid installing these bundles!

Unfortunately, I did follow the cpan instructions and I installed Bundle::CPAN. I think that shows up in my find results that I posted earlier:

$ sudo find / -type f -name CPAN.pm

/System/Library/Perl/5.8.6/CPAN.pm
/Users/me/.cpan/Bundle/CPAN.pm   <----HERE***
/Users/me/my_tar_extractions/perl-5.10.1/lib/CPAN.pm
/usr/local/lib/perl5/5.10.1/CPAN.pm
[download]