error after updated perl5.8 from 5.8.6 to 5.8.7

[Zhang Qing]

on FreeBSD srim.hn.org 6.0-STABLE FreeBSD 6.0-STABLE #0: Tue Nov 15
11:01:02 CST 2005 root at srim.hn.org:/usr/obj/usr/src/sys/NUCLEUS  i386

have  done 'perl-after-upgrade' according to

20050624:
AFFECTS: users of lang/perl5.8
AUTHOR: tobez at FreeBSD.org <mailto:tobez at FreeBSD.org>

lang/perl5.8 has been updated to 5.8.7. You should update everything
depending on perl. The easiest way to do that is to use
perl-after-upgrade script supplied with lang/perl5.8. Please see
its manual page for details.

but when executing:

srim# cd /usr/ports/www/mod_perl2
srim# make install clean && rehash
************************************************************
NOTE: Version 2.0.0-RC5 and higher of mod_perl
significantly change the API - old code *will* break!
See http://perl.apache.org/docs/2.0/rename.html

Hit Ctrl-C to abort now, if this is of concern.
************************************************************
===> Vulnerability check disabled, database not found
===> Extracting for mod_perl2-2.0.2,2
=> MD5 Checksum OK for mod_perl-2.0.2.tar.gz.
=> No SHA256 checksum recorded for mod_perl-2.0.2.tar.gz.
===> mod_perl2-2.0.2,2 depends on file: /usr/local/bin/perl5.8.7 - found
===> Patching for mod_perl2-2.0.2,2
===> mod_perl2-2.0.2,2 depends on file: /usr/local/bin/perl5.8.7 - found
===> Applying FreeBSD patches for mod_perl2-2.0.2,2
===> mod_perl2-2.0.2,2 depends on file: /usr/local/sbin/apxs - found
===> mod_perl2-2.0.2,2 depends on file: /usr/local/bin/perl5.8.7 - found
===> mod_perl2-2.0.2,2 depends on file: /usr/local/sbin/apxs - found
===> Configuring for mod_perl2-2.0.2,2
/libexec/ld-elf.so.1:
/usr/local/lib/perl5/site_perl/5.8.7/mach/auto/Cwd/Cwd.so: Undefined
symbol "Perl_Gthr_key_ptr"
*** Error code 1

Stop in /usr/ports/www/mod_perl2.
srim#

it can't make mod_perl2, the key error is Undefined symbol
"Perl_Gthr_key_ptr", what this meaning? and how to correct it?