Zend Wurfl Mobile Server Error - php

Question

Hi i try to add mobile template into current zend application but it return server error.
Following are my configuration as i follow on several sites.
application.in
resources.frontController.plugins[] = "Rate_Application_Mobile"
resources.useragent.wurflapi.wurfl_api_version = "1.1"
resources.useragent.wurflapi.wurfl_lib_dir = APPLICATION_PATH "/../library/wurfl/WURFL/"
resources.useragent.wurflapi.wurfl_config_file = APPLICATION_PATH "/configs/wurfl-config.php"
wurfl-config.php
<?php
$resourcesDir = dirname(__FILE__) . '/../../data/wurfl/';
$wurfl['main-file'] = $resourcesDir . 'wurfl-2.0.27.zip';
$wurfl['patches'] = array($resourcesDir . 'web_browsers_patch.xml');
$persistence['provider'] = 'file';
$persistence['dir'] = $resourcesDir . 'cache/';
$cache['provider'] = null;
$configuration['wurfl'] = $wurfl;
$configuration['persistence'] = $persistence;
$configuration['cache'] = $cache;
Mobile Plugin
/var/www/library/Rate/Application/Mobile.php
class Rate_Application_Mobile extends Zend_Controller_Plugin_Abstract
{
public function dispatchLoopStartup(Zend_Controller_Request_Abstract $req)
{
$front = Zend_Controller_Front::getInstance();
$bootstrap = $front->getParam("bootstrap");
$userAgent = $bootstrap->getResource('useragent');
$device = $userAgent->getDevice(); --> this part return server error when switching to mobile browser, otherwise it return desktop when view as desktop browser
}
}
Thanks!!
Update: Error return as follow
Warning: include(/var/www/library/wurfl/WURFL/Storage/.php): failed to open stream: No such file or directory in /var/www/library/wurfl/WURFL/ClassLoader.php on line 42
Warning: include(): Failed opening '/var/www/library/wurfl/WURFL/Storage/.php' for inclusion (include_path='/var/www/application/../library:/var/www/library:.:/usr/share/php:/usr/local/Zend/library') in /var/www/library/wurfl/WURFL/ClassLoader.php on line 42
Fatal error: Class 'WURFL_Storage_' not found in /var/www/library/wurfl/WURFL/Storage/Factory.php on line 43

Answer 1

This is an answer I gave in the comments above, copied and pasted just for the sake of upvoting and accepting.
This is PHP error stating that class file was not found. You're including empty name PHP file, so WURFL probably can't detect what it needs to load. Please do a debug_backtrace() before error line in ClassLoader.php:42 (first error) and check what storage it tries / needs to load in Factory.php:43. If it's this file: Factory.php you're trying to load a file provider which should be specified in provider config tree which you do provide, but it's not read.
For now please clear ZF cache, and check if
$persistence['provider'] = 'file';
$cache['provider'] = null;
$configuration['persistence'] = $persistence;
do not interfere.