'Mage_Core_Model_Config_Element' is not allowed'

Hey guys,
 
in found a issue my eception.log

2017-12-20T14:47:12+00:00 ERR (3): 
exception 'Exception' with message 'Serialization of 'Mage_Core_Model_Config_Element' is not allowed' in /../.../.../.../.../.../magento/app/code/local/JoomlArt/JmProducts/Block/List.php:229
Stack trace:
#0 /../.../.../.../.../.../magento/app/code/local/JoomlArt/JmProducts/Block/List.php(229): serialize(Object(Mage_Catalog_Model_Resource_Product_Collection))
#1 /../.../.../.../.../.../magento/app/code/local/JoomlArt/JmProducts/Block/List.php(159): JoomlArt_JmProducts_Block_List->getProductCollection()
#2 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Block/Abstract.php(922): JoomlArt_JmProducts_Block_List->_beforeToHtml()
#3 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/Email/Template/Filter.php(208): Mage_Core_Block_Abstract->toHtml()
#4 [internal function]: Mage_Core_Model_Email_Template_Filter->blockDirective(Array)
#5 /../.../.../.../.../.../magento/lib/Varien/Filter/Template.php(163): call_user_func(Array, Array)
#6 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/Email/Template/Filter.php(560): Varien_Filter_Template->filter('<div>{{block ty...')
#7 /../.../.../.../.../.../magento/app/code/local/JoomlArt/Jmtabs/Block/Core.php(118): Mage_Core_Model_Email_Template_Filter->filter('<div>{{block ty...')
#8 /../.../.../.../.../.../magento/app/code/local/JoomlArt/Jmtabs/Block/Core.php(66): JoomlArt_Jmtabs_Block_Core->get_Content_Static_Block('31')
#9 [internal function]: JoomlArt_Jmtabs_Block_Core->addTabs_staticblock('M\xC3\xA4nner', 'position-05')
#10 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/Layout.php(348): call_user_func_array(Array, Array)
#11 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/Layout.php(214): Mage_Core_Model_Layout->_generateAction(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#12 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/Layout.php(206): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#13 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/Layout.php(210): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#14 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Controller/Varien/Action.php(344): Mage_Core_Model_Layout->generateBlocks()
#15 /../.../.../.../.../.../magento/app/code/core/Mage/Cms/Helper/Page.php(113): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#16 /../.../.../.../.../.../magento/app/code/core/Mage/Cms/Helper/Page.php(52): Mage_Cms_Helper_Page->_renderPage(Object(Mage_Cms_IndexController), 'home')
#17 /../.../.../.../.../.../magento/app/code/core/Mage/Cms/controllers/IndexController.php(45): Mage_Cms_Helper_Page->renderPage(Object(Mage_Cms_IndexController), 'home')
#18 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Cms_IndexController->indexAction()
#19 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('index')
#20 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#21 /../.../.../.../.../.../magento/app/code/core/Mage/Core/Model/App.php(365): Mage_Core_Controller_Varien_Front->dispatch()
#22 /../.../.../.../.../.../magento/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#23 /../.../.../.../.../.../magento/index.php(84): Mage::run('', 'store')
#24 {main}

Hope you can help me.

Thank you…