How to solve class not found error in magento 1.9?

Question

I have try to install stamped.io extension, after install back-end showing following error if i click stamped.io setting.

Fatal error: Uncaught Error: Class 'Stamped_Core_Block_Adminhtml_System_Config_Form_Button' not found in /home/abc/public_html/app/code/core/Mage/Core/Model/Layout.php:590 Stack trace: #0 /home/abc/public_html/app/Mage.php(533): Mage_Core_Model_Layout->getBlockSingleton('\n ...') #1 /home/abc/public_html/app/code/core/Mage/Adminhtml/Block/System/Config/Form.php(310): Mage::getBlockSingleton('\n ...') #2 /home/abc/public_html/app/code/core/Mage/Adminhtml/Block/System/Config/Form.php(229): Mage_Adminhtml_Block_System_Config_Form->initFields(Object(Varien_Data_Form_Element_Fieldset), Object(Mage_Core_Model_Config_Element), Object(Mage_Core_Model_Config_Element)) #3 /home/abc/public_html/app/code/core/Mage/Adminhtml/Block/System/Config/Form.php(164): Mage_Adminhtml_Block_System_Config_Form->_initGroup(Object(Varien_Data_Form), Object(Mage_Core_Model_Config_Element), Object(Mage_Core_Model_Config_Element)) #4 /home/abc/public_html/app/code/core/Mage/Adminhtml/Block/System/Confi in /home/abc/public_html/app/code/core/Mage/Core/Model/Layout.php on line 590

app/code/community/Stamped/Core/Block/AdminHtml/System/Config/Form/Button.php

<?php
class Stamped_Core_Block_Adminhtml_System_Config_Form_Button extends Mage_Adminhtml_Block_System_Config_Form_Field
{
    /*
     * template
     */
    protected function _construct()
    {
        parent::_construct();
        $this->setTemplate('stamped/system/config/button.phtml');
    }

    /**
     * return html
     *
     * @param  Varien_Data_Form_Element_Abstract $element
     * @return string
     */
    protected function _getElementHtml(Varien_Data_Form_Element_Abstract $element)
    {
        return $this->_toHtml();
    }
}

How to solve the class missing error?

Answer 1

At first sight, I could identify that:

app/code/community/Stamped/Core/Block/AdminHtml/System/Config/Form/Button.php

path should be:

app/code/community/Stamped/Core/Block/Adminhtml/System/Config/Form/Button.php

Notice the typo in AdminHtml, which should be Adminhtml.

Please fix this and let me know if you find any other problem further.