I tried to launch gccg_package with different versions libwww-perl but it gave same errors:
dev-perl/libwww-perl-6.30.0:
$ ./gccg_package status
---
Fetching module list [1] http://gccg.sourceforge.net/modules/available.xml
** GET http://gccg.sourceforge.net/modules/available.xml ==> Can't locate object method "flush" via package "IO::File" at /usr/lib64/perl5/vendor_perl/5.12.4/LWP/UserAgent.pm line 510.
dev-perl/libwww-perl-6.40.0:
$ ./gccg_package status
---
Fetching module list [1] http://gccg.sourceforge.net/modules/available.xml
** GET http://gccg.sourceforge.net/modules/available.xml ==> Can't locate object method "flush" via package "IO::File" at /usr/lib64/perl5/vendor_perl/5.12.4/LWP/UserAgent.pm line 535.
dev-perl/libwww-perl-6.50.0:
$ ./gccg_package status
---
Fetching module list [1] http://gccg.sourceforge.net/modules/available.xml
** GET http://gccg.sourceforge.net/modules/available.xml ==> Can't locate object method "flush" via package "IO::File" at /usr/lib64/perl5/vendor_perl/5.12.4/LWP/UserAgent.pm line 535.
Rev: 728
Gentoo Linux AMD64
The current stable LWP version is only 6.05 (though Perl itself is at 5.18.0).
Unlike later versions, 5.12.4 apparently does not autoinclude IO::File, and that's what might be causing the error. Try editing gccg_package so that after line 1196 (which is "LWP::UserAgent->import();"), you add another line:
IO::File->import();
Also note that if you keep the SVN repositories up to date, gccg_package isn't really necessary for anything.