Need help to activate the Twitter API plugin please

Dear Team and community, I need help to install elgg, everything works but when i click view my site in admin panel there is an error : http://www.the4leafclover.com/activity plus some of plug ins seems not activated: here is what i can read for example:

Twitter API 1.8

This plugin has unmet dependencies and cannot be activated. Check dependencies under more info.

Allows users to authenticate their Elgg account with Twitter.

Author: Core developers - http://www.elgg.org/

I don't get what i did wrong can someone explain to me please.
Best regards
Amandine