Problems with Memcached

Greetings. I am getting an error message on General Configuration on the Caching Driver option. When I set it to Memcached (which is installed on my server), an error message says “Cannot Connect to Memcached, using File Driver instead”.

At first, I used the following on my config file:

$config['cache_driver'] = 'memcached';

Based on another suggestion, I then used:

$config['cache_driver'] = 'memcached';
$config['memcached'] = array(
  array(
    'host' => 'localhost',
    'port' => (removed),
    'weight' => 1,
  )
);

Any suggestions?

Just for the record, array is in there twice, which I suspect is a mistake on the part of the person who posted the code. But it doesn’t work with array in there once, either.