Slony lib não encontrado

Tentando executar o script de configuração slony de exemplo na documentação, mas obtendo o seguinte erro:

postgres$ /tmp/slonik_example.sh 
<stdin>:8: PGRES_FATAL_ERROR load '$libdir/slony1_funcs';  - ERROR:  could not access file "$libdir/slony1_funcs": No such file or directory 
<stdin>:8: Error: the extension for the Slony-I C functions cannot be loaded in database 'dbname=my_primary host=localhost user=warfish password=coalitions' 

No entanto, a variável LIBDIR está definida corretamente:

postgres$ ./pg_config 
BINDIR = /opt/local/lib/postgresql90/bin 
DOCDIR = /opt/local/share/doc/postgresql 
HTMLDIR = /opt/local/share/doc/postgresql 
INCLUDEDIR = /opt/local/include/postgresql90 
PKGINCLUDEDIR = /opt/local/include/postgresql90 
INCLUDEDIR-SERVER = /opt/local/include/postgresql90/server 
LIBDIR = /opt/local/lib/postgresql90 

E a lib está presente:

ls -l /opt/local/lib/postgresql90/slony1_funcs.so 
-rwxr-xr-x  1 root  admin  34944 Feb 17 16:20 /opt/local/lib/postgresql90/slony1_funcs.so 

O roteiro é o seguinte:

cat /tmp/slonik_example.sh 
#!/bin/sh 

CLUSTERNAME=slony_example; 
/opt/local/lib/postgresql90/bin/slonik <<_EOF_ 
define CLUSTERNAME slony_example; 
cluster name = @CLUSTERNAME; 
node 1 admin conninfo = 'dbname=my_primary host=localhost user=user1 password=pw'; 
node 2 admin conninfo = 'dbname=my_rep host=localhost user=user1 password=pw'; 
#-- 
# init the first node. Its id MUST be 1. This creates the schema # _$CLUSTERNAME containing all replication system specific database # objects. 
#-- 
init cluster ( id=1, comment='Master Node'); 
#-- 
# Slony-I organizes tables into sets. The smallest unit a node can # subscribe is a set. The following commands create one set containing # all 4 pgbench tables. The master or origin of the set is node 1. 
#-- 
create set (id=1, origin=1, comment='All pgbench tables'); 
set add table (set id=1, origin=1, id=1, fully qualified name='public.pgbench_accounts', comment='accounts table'); 
set add table (set id=1, origin=1, id=2, fully qualified name='public.pgbench_branches', comment='branches table'); 
set add table (set id=1, origin=1, id=3, fully qualified name='public.pgbench_tellers', comment='tellers table'); 
set add table (set id=1, origin=1, id=4, fully qualified name='public.pgbench_history', comment='history table'); 
#-- 
# Create the second node (the slave) tell the 2 nodes how to connect to Slony-I 2.1.1 Documentation 10 / 163 
# each other and how they should listen for events. 
#-- 
store node (id=2, comment = 'Slave node', event node=1); 
store path (server = 1, client = 2, conninfo='dbname=my_primary host=localhost user=user1 password=pw'); 
store path (server = 2, client = 1, conninfo='dbname=my_rep host=localhost user=user1 password=pw'); 
_EOF_ 

Leia no documento que provavelmente a lib não está no lugar correto ou $ libdir não está definido corretamente, mas tudo parece estar no lugar. Estou perdendo algo mais que não conheço?