tablespace restore

Hello

I use postgres 8.3.12 on machineA and 8.4.5 on machineB.

On machineA I have created a tablespace with
CREATE TABLESPACE tablelocation_name LOCATION '/my/location/machineA';

I then created a database with
CREATE DATABASE db_name TABLESPACE tablelocation;

I created tables, inserted data and created indexes.

I now want to "move" the db from '/my/location/machineA' of machine A to
'/other/location/machineB' of machine B. My question is how I can do a
filesystem backup/restore (I want to move the indexes too - too time
consuming to reindex).

Machine B already has a postgres running, and postgres on machine B
already has other databases. During this process I have no problem of
shutting down postgres.

I have tried some things unsuccessfully:
1) - stop postgres on machine B
- copy dir of tablelocation of machine A to
'/other/location/machineB' on machine B
- start postgres on machine B
- CREATE TABLESPACE tablelocation_name LOCATION
'/other/location/machineB';
ERROR: directory "/other/location/machineB" is not empty

Regards
Vangelis