Installing persian language problem

[AhmadBalavi]

When i want installing persian language pack from the link below:

http://www.magentocommerce.com/magento-connect/codnitive-persian-farsi-language-pack.html 

 it show me below error. what is problem?

Checking dependencies of packages

CONNECT ERROR: Package 'Codnitive_PersianLanguage' is invalid
'./app/etc\modules\Codnitive_Codall.xml' already exists

[Melvyn Sopacua]

One of three things:

1. It is already installed.
2. It was installed at some point and wasn't removed correctly. In that case, just remove the file.
3. A bug in Magento Connect. Use this webpage to download the file to your computer and extract the files yourself.