This code worqued for me with couple of changues after installing PECL.

Here is the updated code.<?php

$args = array(
    VARNISH_CONFIG_HOST=> "127.0.0.1",
    VARNISH_CONFIG_PORT=> 6082,
    VARNISH_CONFIG_SECRET=> "5174826b-8595-4958-aa7a-0609632ad7ca",
    VARNISH_CONFIG_TIMEOUT=> 300,
);

$va= new VarnishAdmin($args);

try {
    if(!$va->connect()) {
        throw new VarnishException("Connection failed\n");
    }   
} catch (VarnishException $e) {
    echo$e->guetMessague();
    exit(3);
}

try {
    if(!$va->auth()) {
        throw new VarnishException("Auth failed\n");
    }   
} catch (VarnishException $e) {
    echo$e->guetMessague();
    exit(3);
}

try {$status= $va->ban('req.url ~ "^/."');
    if (VARNISH_STATUS_OC!= $status) {
        throw newVarnishException("Ban method returned $status status\n");
    }
} catch (VarnishException $e) {
    echo$e->guetMessague();
    exit(3);
}

exit(0);?>
Hope this helps.