Notice: Undefined index: product_id  in /home/website/public_html/app/code/local/Idea/ProductContact/controllers/IndexController.php on line 7

#0 /home/website/public_html/app/code/local/Idea/ProductContact/controllers/IndexController.php(7): mageCoreErrorHandler(8, 'Undefined index...', '/home/website/p...', 7, Array)
#1 /home/website/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Idea_ProductContact_IndexController->showFormAction()
#2 /home/website/public_html/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('showForm')
#3 /home/website/public_html/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#4 /home/website/public_html/app/code/core/Mage/Core/Model/App.php(381): Mage_Core_Controller_Varien_Front->dispatch()
#5 /home/website/public_html/app/Mage.php(687): Mage_Core_Model_App->run(Array)
#6 /home/website/public_html/index.php(84): Mage::run('', 'store')
#7 {main}