could not open file "global/pg_database"

Dear PostgreSQL users,

I'm running postgreSQL 8.1 (installed with YaST) on a Suse 10.2 machine.
My $PGDATA variable is /home/postgres/data

When I initiate the databases with initdb without argument. It seems to works
as I get this :
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale en_US.UTF-8.
The default database encoding has accordingly been set to UTF8.

fixing permissions on existing directory /home/postgres/data ... ok
creating directory /home/postgres/data/global ... ok
creating directory /home/postgres/data/pg_xlog ... ok
creating directory /home/postgres/data/pg_xlog/archive_status ... ok
creating directory /home/postgres/data/pg_clog ... ok
creating directory /home/postgres/data/pg_subtrans ... ok
creating directory /home/postgres/data/pg_twophase ... ok
creating directory /home/postgres/data/pg_multixact/members ... ok
creating directory /home/postgres/data/pg_multixact/offsets ... ok
creating directory /home/postgres/data/base ... ok
creating directory /home/postgres/data/base/1 ... ok
creating directory /home/postgres/data/pg_tblspc ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 1000
creating configuration files ... ok
creating template1 database in /home/postgres/data/base/1 ... ok
initializing pg_authid ... ok
enabling unlimited row size for system tables ... ok
initializing dependencies ... ok
creating system views ... ok
loading pg_description ... ok
creating conversions ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the -A option the
next time you run initdb.

Success. You can now start the database server using:

postmaster -D /home/postgres/data
or
pg_ctl -D /home/postgres/data -l logfile start

But it I try to run the daemon with

pg_ctl -D /home/postgres/data -l logfile start, I get this :
Postmaster running (and that's all, nothing is added in logfile) ... and the
server does not seem to work.

If I try create a database

createdb testdb

createdb: could not connect to database postgres: FATAL: could not open
file "global/pg_database": No such file or directory

If I try to create a user

createuser sylvain
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n
createuser: could not connect to database postgres: FATAL: could not open
file "global/pg_database": No such file or directory

It seems that the server cannot get access to global/pg_database but why? Even
if all the of this file (777) are available. It cannot get access to it?

Does somebody as any idea?

Thanks a lot,

Sylvain