title: Wrong tab configuration on Magento
body: <p>I have a huge problem with an magento extension I developed. Localhost everything is fine but when I deploy, it get this error.</p>
  
  <p>Wrong tab configuration</p>
  
  <pre><code>#0 [internal function]: Mage_Adminhtml_Block_Widget_Tabs-&gt;addTab('pricematrix', 'tab_pricematrix')
  #1 /var/www/vhosts/discountprint.dk/httpdocs/app/code/core/Mage/Core/Model/Layout.php(347): call_user_func_array(Array, Array)
  #2 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Model/Layout.php(213): Mage_Core_Model_Layout-&gt;_generateAction(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
  #3 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Model/Layout.php(209): Mage_Core_Model_Layout-&gt;generateBlocks(Object(Mage_Core_Model_Layout_Element))
  #4 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(343): Mage_Core_Model_Layout-&gt;generateBlocks()
  #5 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(270): Mage_Core_Controller_Varien_Action-&gt;generateLayoutBlocks()
  #6 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Adminhtml/Controller/Action.php(263): Mage_Core_Controller_Varien_Action-&gt;loadLayout(Array, true, true)
  #7 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Adminhtml/controllers/Catalog/ProductController.php(246): Mage_Adminhtml_Controller_Action-&gt;loadLayout(Array)
  #8 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Adminhtml_Catalog_ProductController-&gt;editAction()
  #9 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(253): Mage_Core_Controller_Varien_Action-&gt;dispatch('edit')
  #10 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard-&gt;match(Object(Mage_Core_Controller_Request_Http))
  #11 /var/www/vhosts/something.dk/httpdocs/app/code/core/Mage/Core/Model/App.php(340): Mage_Core_Controller_Varien_Front-&gt;dispatch()
  #12 /var/www/vhosts/something.dk/httpdocs/app/Mage.php(627): Mage_Core_Model_App-&gt;run(Array)
  #13 /var/www/vhosts/something.dk/httpdocs/index.php(80): Mage::run('', 'store')
  #14 {main}
  </code></pre>
  
  <p>I Googled it for hours but can't find any useful information. My magento version is 1.5.0.1</p>
  
  <p>Hope you can help</p>