无法安装magento补丁6788

I was trying to install the new magento patch 6788 on my Magento CE1.6.1.0, but I cannot apply it successfully because of the following errors:

Checking if patch can be applied/reverted successfully...
ERROR: Patch can't be applied/reverted successfully.

patching file .htaccess
Hunk #1 FAILED at 184.
1 out of 1 hunk FAILED -- saving rejects to file .htaccess.rej patching file .htaccess.sample 
patching file app/code/core/Mage/Admin/Model/Block.php
patching file app/code/core/Mage/Admin/Model/Resource/Block.php
patching file app/code/core/Mage/Admin/Model/Resource/Block/Collection.php
patching file app/code/core/Mage/Admin/Model/Resource/Variable.php
patching file app/code/core/Mage/Admin/Model/Resource/Variable/Collection.php
patching file app/code/core/Mage/Admin/Model/Variable.php
patching file app/code/core/Mage/Admin/etc/config.xml
patching file app/code/core/Mage/Admin/sql/admin_setup/upgrade-1.6.1.0-1.6.1.1.php
patching file app/code/core/Mage/Admin/sql/admin_setup/upgrade-1.6.1.1-1.6.1.2.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Block.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Block/Edit.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Block/Edit/Form.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Block/Grid.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Variable.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Variable/Edit.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Variable/Edit/Form.php
patching file app/code/core/Mage/Adminhtml/Block/Permissions/Variable/Grid.php
patching file app/code/core/Mage/Adminhtml/controllers/Permissions/BlockController.php
patching file app/code/core/Mage/Adminhtml/controllers/Permissions/VariableController.php
patching file app/code/core/Mage/Adminhtml/etc/adminhtml.xml
patching file app/code/core/Mage/Catalog/Model/Product/Option/Type/File.php
 patching file app/code/core/Mage/Core/Controller/Request/Http.phppatching file app/code/core/Mage/Core/Controller/Varien/Router/Admin.php
patching file app/code/core/Mage/Core/Helper/UnserializeArray.php
patching file app/code/core/Mage/Core/Model/Email/Template/Filter.php
patching file app/code/core/Mage/Core/Model/Resource/Setup.php
patching file app/code/core/Mage/Core/etc/config.xml
patching file app/code/core/Mage/Core/etc/system.xml
patching file app/code/core/Mage/Customer/Block/Account/Changeforgotten.php
patching file app/code/core/Mage/Customer/Block/Account/Resetpassword.php
patching file app/code/core/Mage/Customer/controllers/AccountController.php
patching file app/code/core/Mage/Downloadable/Model/Product/Type.php
patching file app/code/core/Mage/Eav/Model/Resource/Attribute/Collection.php
patching file app/code/core/Mage/Sales/Model/Resource/Order/Item/Collection.php
patching file app/code/core/Mage/Sales/controllers/DownloadController.php
Hunk #1 FAILED at 48.
Hunk #2 FAILED at 66.
Hunk #3 FAILED at 176.
3 out of 3 hunks FAILED -- saving rejects to file 
......

I have replaced the two failed files (.htaccess and Sales/controllers/DownloadController.php) with the original magento files, but still getting the same error.

Please give me some ideas about why does it happen.

Thank you.

It's definitely seems to by the .htaccess file, try to find the exact version for the CE1.6.1.0.
Also make sure that you don't deleted any file/folders from the original. I deleted some skins that I wasn't using (Modern and Iphone) and had to restore them.
I also restored the .htaccess.sample file.