initdb problem => creating template1 database in C:/Program Files/.. ... child process exited with exit code 1

Hi, I have got an error during initdb part of my PostgreSQL 8.3 installation
My initdb.log file says the following :

# The files belonging to this database system will be owned by user "SYSTEM".
# This user must also own the server process.

# The database cluster will be initialized with locale Turkish_Turkey.
# The default text search configuration will be set to "turkish".

# creating directory C:/Program Files/PostgreSQL/8.3/data ... ok
# creating subdirectories ... ok
# selecting default max_connections ... 50
# selecting default shared_buffers/max_fsm_pages ... 32MB/204800
# creating configuration files ... ok
# creating template1 database in C:/Program Files/PostgreSQL/8.3/data/base/1 ... child process exited with exit code 1
# initdb: removing data directory "C:/Program Files/PostgreSQL/8.3/data"

I have got the above error on Windows XP Media Center Edition and I have got no such error if I install PostgreSQL 8.3 on the Windows XP Prof SP2.
And after the error message is shown all of the PostgreSQL installation directory is deleted by the installation wizard.

Do anyone have any idea about this problem ?
Thanks..

Fatih Batuk
fatihbatuk.blogspot.com

Hacettepe University, Turkiye