get_instance() does not seem to load cacheing classes when called in the Language files

[eluser]Unknown[/eluser]
Background: I am trying to move my Language files into a DB structure so I can easily build
an interface for my client to change the copy without having to directly modify Language files (think CMS).
I use memcached cache support on my DB Layer

The issue I have is that when I instantiating a CI object using the get_instance() function in the language file then use it to call my query I get a "Fatal error: Call to a member function is_supported() on a non-object". It seems the Cache Library has not been loaded.

Anyone know if I can load the cache library manually?
Any other suggestions?

Here is the code I think is relevant.

common_lang.php (autoloaded)

Code:

<?php
$ci =& get_instance();
$ci->load->model('SystemModel');
$ci->load->config();
$values = $ci->SystemModel->getLangValues($ci->config->item('language'));
foreach ($values as $pair){
    $lang[$pair['field']] = $pair['copy'];
}

systemmodal.php

Code:

public function getLangValues($lang){

       $sql = <<<SQL
       SELECT
            language_fields.field as field,
            language_fields.category as category,
            language_field_copy.copy as copy
       FROM
            language_fields,
            language_field_copy
       WHERE
            language_field_copy.field_id = language_fields.id
       AND
            language_field_copy.language = ?

SQL;
      
        $this->cacheArray['function'] = 'LangueValues';
        $this->cacheArray['id'] = 'all';
      return  $this->query($sql,array($lang),$this->cacheArray);
   }

My_Model (adds caching support)

Code:

public function query($sql, $binds=false,  $cacheArray = null, $returnObject=true) {
        log_message('debug', 'My Model Query Called:');
        $timeOut = (!empty($cacheArray['cacheTime']))?$cacheArray['cacheTime']:$this->config->item('cacheTimeOut');

        // Hook into Memcache here?
        // I want to explicitly Clear cache so looking for the false case not empty value

         if((empty($cacheArray))|| (!$this->CI->cache->memcached->is_supported()) ){
            log_message('debug', 'Cache not attempted: ' . $cacheArray['group'] .':'.$cacheArray['function'].':'. $cacheArray['id']);
            if($returnObject === true){
                $result = $this->DB->query($sql, $binds);
                if(is_object($result)) {
                    return  $result->result_array();
                } else {
                    return true;
                }
            } else {
                return $this->DB->query($sql, $binds);
            }
        } else {
             if((!empty($cacheArray['clear'])) && ($cacheArray['clear'] === TRUE)) {
                $return = $this->DB->query( $sql, $binds);
                $this->extendedquerylib->deleteCache($cacheArray);
            } else {
                if (!$return = $this->extendedquerylib->getCache($cacheArray)) {
                    if ($result = $this->DB->query($sql, $binds)) {
                        $return = $result->result_array();
                        $this->extendedquerylib->addCache($cacheArray, $return, $timeOut);
                    }else {
                        $return = false;
                    }
                }
            }

            return $return;
        }
    }

I appreciate any help!!