net-snmp error on FreeBSD

Error message :

/libexec/ld-elf.so.1:
/usr/local/lib/perl5/site_perl/5.8.9/mach/auto/NetSNMP/default_store/default_s
tore.so:
Undefined symbol "Perl_Gthr_key_ptr"
*** Error code 1

Stop in /usr/ports/net-mgmt/net-snmp/work/net-snmp-5.4.2.1.
*** Error code 1

I reinstall perl-5.8 but no use. Finally, I solve the problem by un-checked the option “Use 64 bit integers (on i386)” before compiling perl in the make config menu.