Error during a dump (ts_selectivity, not found)

Hello all,

I am trying to restore a database on a server from a dump taken from a
different server, but I get the following error:

==============================================================================================================
# pg_restore -Upgsql -d db14 /mnt/backup/__initial_move__/db01_20110114.dump
Password:
pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 25; 1255 2299293
FUNCTION tsmatchsel_wrapper(internal, oid, internal, integer) pgsql
pg_restore: [archiver (db)] could not execute query: ERROR:  could not
access file "$libdir/ts_selectivity": No such file or directory
     Command was: CREATE FUNCTION tsmatchsel_wrapper(internal, oid,
internal, integer) RETURNS double precision
     LANGUAGE c
     AS '$libdir...
pg_restore: [archiver (db)] could not execute query: ERROR:  function
public.tsmatchsel_wrapper(internal, oid, internal, integer) does not exist
     Command was: ALTER FUNCTION public.tsmatchsel_wrapper(internal,
oid, internal, integer) OWNER TO pgsql;
pg_restore: [archiver (db)] Error from TOC entry 2189; 2617 2299294
OPERATOR @-@ pgsql
pg_restore: [archiver (db)] could not execute query: ERROR:  function
tsmatchsel_wrapper(internal, oid, internal, integer) does not exist
     Command was: CREATE OPERATOR @-@ (
     PROCEDURE = ts_match_qv,
     LEFTARG = tsquery,
     RIGHTARG = tsvector,
     COMMUTATOR = @-@,
    ...
pg_restore: [archiver (db)] could not execute query: ERROR:  operator
does not exist: tsquery public.@-@ tsvector
     Command was: ALTER OPERATOR public.@-@ (tsquery, tsvector) OWNER TO
pgsql;
pg_restore: [archiver (db)] Error from TOC entry 2185; 2617 2299295
OPERATOR @-@ pgsql
pg_restore: [archiver (db)] could not execute query: ERROR:  function
tsmatchsel_wrapper(internal, oid, internal, integer) does not exist
     Command was: CREATE OPERATOR @-@ (
     PROCEDURE = ts_match_vq,
     LEFTARG = tsvector,
     RIGHTARG = tsquery,
     COMMUTATOR = @-@,
    ...
pg_restore: [archiver (db)] could not execute query: ERROR:  operator
does not exist: tsvector public.@-@ tsquery
     Command was: ALTER OPERATOR public.@-@ (tsvector, tsquery) OWNER TO
pgsql;

WARNING: errors ignored on restore: 6
==============================================================================================================

I searched for the library ts_selectivity, but all in vain.

Any advice/hint is very much appreciated.

Best Regards,
Ahmed Ossama