failed to install posgrest

Hi I am trying to install the portgres of 64btis in centos 5.6 but at the
next command ./postgresql-8.3.4-1-linux-x64.bin
the results are as follows:

[root(at)yaku programas]# ./postgresql-8.3.4-1-linux-x64.bin
----------------------------------------------------------------------------
Welcome to the PostgreSQL Setup Wizard.

----------------------------------------------------------------------------
Please specify the directory where PostgreSQL will be installed.

Installation Directory [/opt/PostgreSQL/8.3]: /usr/local/postgresql_8.3

----------------------------------------------------------------------------
Please select a directory under which to store your data.

Data Directory [/usr/local/postgresql_8.3/data]: /base/data

*Error: The existing data directory (catalog version: 200611241) is not
compatible with this server (catalog version: 200711281).*
Press [Enter] to continue :

thanks for help