title: Magento error: Module "Mage_Api" requires module "Mage_Core"
body: <p>my production site gone away and for no reason. I know last extension I have installed, but that was three days ago. I get this error on every page:</p>
  
  <pre><code>a:4:{i:0;s:46:"Module "Mage_Api" requires module "Mage_Core".";i:1;s:702:"#0 /app/code/core/Mage/Core/Model/Config.php(804): Mage::throwException('Module "Mage_Ap...')
  #1 /app/code/core/Mage/Core/Model/Config.php(769): Mage_Core_Model_Config-&gt;_sortModuleDepends(Array)
  #2 /app/code/core/Mage/Core/Model/Config.php(315): Mage_Core_Model_Config-&gt;_loadDeclaredModules()
  #3 /app/code/core/Mage/Core/Model/App.php(396): Mage_Core_Model_Config-&gt;loadModules()
  #4 /app/code/core/Mage/Core/Model/App.php(329): Mage_Core_Model_App-&gt;_initModules()
  #5 /app/Mage.php(627): Mage_Core_Model_App-&gt;run(Array)
  #6 /index.php(87): Mage::run('', 'store')
  #7 {main}";s:3:"url";s:1:"/";s:11:"script_name";s:10:"/index.php";}
  </code></pre>
  
  <p>What can I do to return my production site to work?</p>
  
  <p>P.S. Mage_Core is not disabled in core_config_data.
  Magento 1.5.1.0</p>
  
  <p><strong>SOLVED</strong>: I had wrong permissions on my config files under app/etc folder.</p>