Magento extension giving problem at time of install

I am using extension in magento "J2TRememberMe", but at installation it's giving me problems. It's showing a message like开发者_StackOverflow:

"Failed to download magento-community/J2TRememberMe within preferred state "stable", latest release is version 1.0, stability "beta", use "channel://connect.magentocommerce.com/community/J2TRememberMe-1.0" to install

Cannot initialize 'channel://connect.magentocommerce.com/community/J2TRememberMe', invalid or missing package file

Install Errors
Package "channel://connect.magentocommerce.com/community/J2TRememberMe" is not valid
PEAR ERROR: install failed"

Does anyone have any idea how to resolve it ?

Thanks

in the tab settings, change the preferred state from "stable" to "beta"

Magento Connect uses PEAR on the backend. PEAR is a package management system for PHP that grew out of the PHP Code repository of the same name. Try using the key

community/J2TRememberMe-1.0

to install your module. Module Keys look to be PEAR URIs.