is there anything wrong in my configuration???

# ./configure --prefix=/usr/local/pgsql --with-python
# make
# make install
# adduser postgres
# mkdir /usr/local/pgsql/data
# chown postgres /usr/local/pgsql/data
# su postgres
% /usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data
% /usr/local/pgsql/bin/pg_ctl -D /usr/local/pgsql/data -l
/usr/local/pgsql/pg_start.log start
%/usr/local/pgsql/bin/createlang plpython template1
createlang: language installation failed: ERROR: unsupported language
"plpython"
HINT: The supported languages are listed in the pg_pltemplate system
catalog.
%

if I try:
# /usr/local/pgsql/bin/createlang -U postgres plpythonu template1
createlang: language installation failed: ERROR: could not load library
"/usr/l
ocal/pgsql/lib/plpython.so": dlopen (/usr/local/pgsql/lib/plpython.so)
failed: /
usr/local/pgsql/lib/plpython.so: Undefined symbol "pthread_create"
#
is there anything wrong in my configuration???
my box is using freebsd 5.0, python 2.4.2, postgresql-8.1.2
thank you all for your help....
Dedy Styawan