Magento Extension Not Installing

I am trying to install the Google Content API for Shopping through magento connect in magento 1.5v.But i am getting the error.Any pointers?

CONNECT ERROR: Package 'Mage_Core_Modules' is invalid
'./app/code/core/Mage/Admin/Model/Acl/Assert/Ip.php' already exists
Package 'Lib_Varien' is invalid
'./lib/Varien/Autoload.php' already exists
Package 'Lib_Google_Checkout' is invalid
'./lib/googlecheckout/googlecart.php' already exists
Package 'Lib_Js_Calendar' is invalid
'./js/calendar/calendar-blue.css' already exists
Package 'Lib_Js_Mage' is invalid
'./js/lib/FABridge.js' already exists
Package 'Lib_Phpseclib' is invalid
'./lib/phpseclib/Crypt/AES.php' already exists
Package 'Mage_Locale_en_US' is invalid
'./app/locale/en_US/Mage_AdminNotification.csv' already exists
Package 'Lib_Mage' is invalid
'./lib/Mage/Archive/Abstract.php' already exists
Package 'Lib_ZF' is invalid
'./lib/Zend/Acl/Assert/Interface.php' al开发者_StackOverflow社区ready exists
Package 'Lib_ZF_Locale' is invalid
'./lib/Zend/Locale/Data/Translation.php' already exists

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I know this is a REALLY old question, but I do have an answer just in case anyone else has this same issue.

To overcome an error like this when installing, simply remove the files that the module is saying "already exists". This will allow the installer to copy the files into their intended locations.

Based on the question, you would delete:

./app/code/core/Mage/Admin/Model/Acl/Assert/Ip.php
./lib/Varien/Autoload.php
./lib/googlecheckout/googlecart.php
./js/calendar/calendar-blue.css
./js/lib/FABridge.js
./lib/phpseclib/Crypt/AES.php
./app/locale/en_US/Mage_AdminNotification.csv
./lib/Mage/Archive/Abstract.php
./lib/Zend/Acl/Assert/Interface.php
./lib/Zend/Locale/Data/Translation.php

After deleting these files, retry the installation and it will work.

Side note: Whoever coded that module is replacing a Mage Core file and /lib/Varien/Autoload.php. Core mods should be copied to app/code/local/ or just overridden the correct way.