Using W3 Total Cache , If you get following error:
Warning: Cannot modify header information – headers already sent by (output started at /home/account/public_html/wp-content/plugins/w3-total-cache/lib/W3/Referrer.php on line 64
Resolve W3 Total Cache Error
You can resolve this by going to the following file in your WordPress blog installation directory:
And update to this:
if you do not find the above mentioned line, just go ahead and add following at the top after opening php tag:
Hope that helps.