The excerpt from the script:

# Check if we are running this as the root user.
if [[ "$(id -u)" != "0" ]]
then
    echo "This script must be run as root."
    exit 1
fi

As far as I can find, the script uses chfs, installp and rpm commands. It means you need to check for two access authentications - aix.fs.manage.change and aix.system.install. Something like:

    if [[ "$(ckauth -A aix.fs.manage.change,aix.system.install)" != "0" ]]
    then
        echo "This script must have aix.fs.manage.change and aix.system.install privileges."
        exit 1
    fi