Twitter Error Installation

I’ve deactivated my twitter plugin but when it’s activated I get this error on https://www.ailinalei.com (with the www):

Warning: Cannot modify header information – headers already sent by (output started at /home/content/i/h/e/iherbst/html/wp-content/plugins/twitter-tools/twitter-tools.php:2) in /home/content/i/h/e/iherbst/html/wp-includes/pluggable.php on line 391

But when I take out the www and only input ailinalei.com, my twitter works fine. Can anyone please help with this? Thanks a bunch!