Magento – Fatal error: Class ‘Altima_Lookbook_Helper_Data’ not found in /home/offerbea/public_html/app/Mage.php on line 547

Magento's autoload should convert the class

Zend_Cache

into an include path of

Zend/Cache.php

and then look for that class in the following folders.

app/code/local/Zend/Cache.php
app/code/community/Zend/Cache.php
app/code/core/Zend/Cache.php
lib/Zend/Cache.php

In a standard install, it loads from lib/Zend/Cache.php. So, the first thing I'd do is make sure the lib/Zend/Cache.php is there, and there is not a file at the other locations. If there is a file at the other location(s), take a look inside and make sure a class named Zend_Cache is actually defined.

If the file's there, then it sounds like it's not being loaded correctly. The next debugging step I'd take is pinpointing the place in app/code/core/Mage/Core/Model/Cache.php where Magento's trying to use Zend_Cache, and make sure the PHP include paths have been setup correctly. Use some var_dump debugging like this.

    #File: app/code/core/Mage/Core/Model/Cache.php
    var_dump(explode(':',get_include_path()));
    exit;
    $this->_frontend = Zend_Cache::factory('Varien_Cache_Core', $backend['type'], $frontend, $backend['options'],
        true, true, true
    );

You should see output that looks something like this

array (size=6)
  0 => string '/path/to/magento/app/code/local' (length=61)
  1 => string '/path/to/magento/app/code/community' (length=65)
  2 => string '/path/to/magento/app/code/core' (length=60)
  3 => string '/path/to/magento/lib' (length=50)
  4 => string '.' (length=1)
  5 => string '/usr/local/php5/lib/php' (length=23)

If lib and the code pools (core, community, local) aren't in there, it meant you may be dealing with a modified app/Mage.php file, or you may be running in Magento compiled mode without having compiled classes (doubtful in your case since the error comes from app/code/core..., but you never know)

Finally, if the paths were setup correctly, I'd look at the autoloader and add some debugging.

#File: lib/Varien/Autoload.php
var_dump($class);
var_dump($classFile);

return include $classFile;

Look for the path the autoloader tries to create for Zend_Cache, and then figure out why it can't load the class.

Hope that helps!

You have declared the Helper class wrongly in config.xml.

Check below for your code snippet

<helpers>
        <concept>
            <class>Wired_concept_Helper</class>
        </concept>
    </helpers>

Here the class should be

<class>Wired_Concept_Helper</class>