我正在开发一个自定义的magento管理后端模块，该模块将有一个包含可添加/编辑项目的网格。这是我的模块结构：

/Mycompany/
---/Mymodule/
-------/Block/
-----------/Adminhtml
--------------/Manageskumappings.php
--------------/Manageskumappings/
-----------------/Grid.php
-----------------/Edit.php
-----------------/Edit/
--------------------/Form.php
-------/controllers/
-----------/Adminhtml
--------------/ManageskumappingsController.php
-------/etc/
-------/Helper/
-------/Model/
-------/sql/

这是我模块的config.xml:

<?xml version="1.0"?>
<config>
    <!-- Module Info -->
    <modules>
        <Mycompany_Mymodule>
            <version>2.0.0</version>
        </Mycompany_Mymodule>
    </modules>
    
    <!-- Module Globals -->
    <global>
    
        <!-- Register Helper -->
        <helpers>
            <mycompany_mymodule>
                <class>Mycompany_Mymodule_Helper</class>
            </mycompany_mymodule>
        </helpers>
        
        <!-- Register Models -->
        <models>
            <mycompany_mymodule>
                <class>Mycompany_Mymodule_Model</class>
                <resourceModel>mycompany_mymodule_mysql4</resourceModel>
            </mycompany_mymodule>
            <mycompany_mymodule_mysql4>
                <class>Mycompany_Mymodule_Model_Mysql4</class>
                <entities>
                    <skumappings>
                        <table>icw_ic_skumappings</table>
                    </skumappings>
                </entities>
            </mycompany_mymodule_mysql4>
        </models>
        
        <!-- Register Resource -->
        <resources>
            <mycompany_mymodule_setup>
                <setup>
                    <module>Mycompany_Mymodule</module>
                </setup>
            </mycompany_mymodule_setup>
        </resources>
        
    </global>
    
    <!-- Admin Router -->
    <admin>
        <routers>
            <adminhtml>
                <args>
                    <modules>
                        <Mycompany_Mymodule after="Mage_Adminhtml">Mycompany_Mymodule_Adminhtml</Mycompany_Mymodule>
                    </modules>
                </args>
            </adminhtml>
        </routers>
    </admin>
    
    <!-- Admin Layout -->
    <adminhtml>
        <layout>
            <updates>
                <mycompany_mymodule>
                    <file>mycompany/mymodule.xml</file>
                </mycompany_mymodule>
            </updates>
        </layout>
    </adminhtml>
    
</config>

这是我的模块adminhtml.xml：

<?xml version="1.0"?>
<config>
    <!-- Menu Setup -->
    <menu>
        <mycompany translate="title" module="mycompany_mymodule">
            <title>Infinite:Connect v2</title>
            <sort_order>0</sort_order>
            <children>
                <mycompany_mymodule_manageskumappings>
                    <title>Manage SKU Mappings</title>
                    <sort_order>1</sort_order>
                    <action>adminhtml/manageskumappings</action>
                </mycompany_mymodule_manageskumappings>
            </children>
        </mycompany>
    </menu>
    
    <!-- Access Control List -->
    <acl>
        <resources>
            <admin>
                <children>                
                    <mycompany translate="title" module="mycompany_mymodule">
                        <title>My Module</title>
                        <sort_order>1</sort_order>
                        <children>
                            <manageskumappings>
                                <title>Manage SKU Mappings</title>
                                <sort_order>1</sort_order>
                            </manageskumappings>
                        </children>
                    </mycompany>
                </children>
            </admin>
        </resources>
    </acl>
    
</config>

我已经创建了以下布局文件：

app/design/adminhtml/default/default/layout/mycompany/mymodule.xml

具有以下定义：

<?xml version="1.0"?>
<layout>
    <!-- Manage SKU Mappings -->
    <adminhtml_manageskumappings_index>
        <reference name="content">
            <block type="mycompany_mymodule/adminhtml_manageskumappings" name="mycompany_mymodule_manageskumappings" />
        </reference>
    </adminhtml_manageskumappings_index>
</layout>

这是我的网格控制器：

app/code/community/Mycompany/Mymodule/controllers/Adminhtml/ManageskumappingsController.php

带有以下代码：

<?php
class Mycompany_Mymodule_Adminhtml_ManageskumappingsController extends Mage_Adminhtml_Controller_Action
{
    protected function _isAllowed()
    {
        return Mage::getSingleton('admin/session')
            ->isAllowed('mycompany/manageskumappings');
    }
    protected function _initAction()
    {
        $this->loadLayout()
            ->_setActiveMenu('mycompany/mycompany_mymodule_manageskumappings')
            ->_title('Manage SKU Mappings');
         
        return $this;
    }
    public function indexAction()
    {  
        $this->_initAction()
            ->renderLayout();
    }
    
    // ... Snipped ...

我已经上传了代码，数据库已经迁移，菜单出现了。当我转到菜单"；我的模块->管理SKU映射"；我看到一张空白页。

我查看了var/log/exception.log，看到了以下内容：

异常"Mage_Core_exception"，在/var/www/public_html/app/Mage.php:595中显示消息"无效的块类型：Mage_Mycompany_Mymodule_block_Adminhtml_Manageskupmappings"

知道可能出了什么问题吗？