dm5k on "W3 Total Cache Update Error"

"W3 Total Cache Error: Files and directories could not be automatically created to complete the installation.

Please execute commands manually

or use FTP form to allow W3 Total Cache make it automatically."

Every time I update W3 Total Cache I get this message. How do I install updates manually?? I have tried clicking the "update via FTP" and that does nothing.

http://wordpress.org/plugins/w3-total-cache/