To prepare the system you must be logged in, or su'd to root.
If you are not root, then su - and type in the root password.
First, check for RedHat installed postgresql and postgresql-server packages.
root# rpm -q postgresql-server
root# rpm -q postgresql
If the packages are installed, you need to remove them.
Be careful of the order you remove the packages. It may complain about dependencies.
root# rpm -e postgresql-devel
root# rpm -e postgresql-jdbc
root# rpm -e postgresql-odbc
root# rpm -e postgresql-perl
root# rpm -e postgresql-python
root# rpm -e postgresql-server
root# rpm -e postgresql-tcl
root# rpm -e postgresql-test
root# rpm -e php-pgsql
root# rpm -e postgresql
Now that you have postgres removed, you can begin the AccelNET installation.