Pb migrating database from Postgres 8.1 to 8.4

Hi all,
I'm facing pbs trying to migrate my current database from Postgres 8.1 to 8.4.

The way I proceed is as 'root' :

su - postgres

createuser -A -R -d -E my_user

createdb --locale C --template template0 --encoding SQL_ASCII my_db

tsearch2_sql='/usr/share/pgsql/contrib/tsearch2.sql'

psql my_db < $tsearch2_sql

pg_restore -d my_db my_db_tar

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Msgs from during 'restore' :

pg_restore: [archiver (db)] Error while PROCESSING TOC:

pg_restore: [archiver (db)] Error from TOC entry 79; 1255 16554 FUNCTION gtsvector_in(cstring) postgres

pg_restore: [archiver (db)] could not execute query: ERROR: could not find function "gtsvector_in" in file "/usr/lib64/pgsql/tsearch2.so"

Command was: CREATE FUNCTION gtsvector_in(cstring) RETURNS gtsvector

AS '$libdir/tsearch2', 'gtsvector_in'

LANGUAGE c STRICT;

pg_restore: [archiver (db)] could not execute query: ERROR: function public.gtsvector_in(cstring) does not exist

Command was: ALTER FUNCTION public.gtsvector_in(cstring) OWNER TO postgres;

pg_restore: [archiver (db)] Error from TOC entry 80; 1255 16555 FUNCTION gtsvector_out(gtsvector) postgres

pg_restore: [archiver (db)] could not execute query: ERROR: could not find function "gtsvector_out" in file "/usr/lib64/pgsql/tsearch2.so"

Command was: CREATE FUNCTION gtsvector_out(gtsvector) RETURNS cstring

AS '$libdir/tsearch2', 'gtsvector_out'

LANGUAGE c STRICT;

pg_restore: [archiver (db)] could not execute query: ERROR: function public.gtsvector_out(gtsvector) does not exist

Command was: ALTER FUNCTION public.gtsvector_out(gtsvector) OWNER TO postgres;

pg_restore: [archiver (db)] Error from TOC entry 350; 1247 16553 TYPE gtsvector postgres

pg_restore: [archiver (db)] could not execute query: ERROR: function gtsvector_in(cstring) does not exist

Command was: CREATE TYPE gtsvector (

INTERNALLENGTH = variable,

INPUT = gtsvector_in,

OUTPUT = gtsvector_out,

ALIGNMENT =...

pg_restore: [archiver (db)] Error from TOC entry 56; 1255 16527 FUNCTION tsquery_in(cstring) postgres

pg_restore: [archiver (db)] could not execute query: ERROR: could not find function "tsquery_in" in file "/usr/lib64/pgsql/tsearch2.so"

Command was: CREATE FUNCTION tsquery_in(cstring) RETURNS tsquery

AS '$libdir/tsearch2', 'tsquery_in'

LANGUAGE c STRICT;

pg_restore: [archiver (db)] Error while PROCESSING TOC:

pg_restore: [archiver (db)] Error from TOC entry 79; 1255 16554 FUNCTION gtsvector_in(cstring) postgres

pg_restore: [archiver (db)] could not execute query: ERROR: could not find function "gtsvector_in" in file "/usr/lib64/pgsql/tsearch2.so"

Command was: CREATE FUNCTION gtsvector_in(cstring) RETURNS gtsvector

AS '$libdir/tsearch2', 'gtsvector_in'

LANGUAGE c STRICT;

............

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Thx in advance for any help
Regards
Chanh