Failures of Net::FTP and LWP during oke testing

There are many "yellow" reports for Math::Pari in the smoke test
database.  They come from failures to download C source code for the
library Math::Pari need.  Net::FTP and LWP fail (kinda mysteriously);
usual `ftp -pinegv' I run for debugging purposes succeeds.

The recent versions of Math::Pari have some code to debug these
failures; however, the debugging output says nothing to me (IIRC, most
of the code to auto-fetch was contributed).  Any help is appreciated.

Thanks,
Ilya

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A good example of the report of failure is
  http://www.nntp.perl.org/group/perl.cpan.testers/2009/11/msg5926497.html
Essentially, the error message is

    Getting GP/PARI from ftp://megrez.math.u-bordeaux.fr/pub/pari/unix/
    Cannot list (Illegal PORT command.
    ):  at utils/Math/PariBuild.pm line 319.

    Can't fetch file with Net::FTP, now trying with LWP::UserAgent...
    Not in this directory, trying `ftp://megrez.math.u-bordeaux.fr/pub/pari/unix/OLD/'...

then it shows that the response via LWP for ..../OLD is empty (of type
text/ftp-dir-listing), and shows that `ftp -pinegv' has no problem
getting the listings (for both directories) and the file.

The code which emits these messages is in
  http://cpansearch.perl.org/src/ILYAZ/Math-Pari-2.0304_00108060102/utils/Math/PariBuild.pm

starting from
  require Net::FTP;