If you look in your cache directory and the css an js files are not there, most likely you have a mod_rewrite problem.
almooj-craig, I'm using NGINX, not Apache. There is no .htaccess and no mod_rewrite. W3 has generated the NGINX rewrite rules for me, but they are not working. All of my other rewrite rules work fine.
The cache directory is writable and I even tried chmod-ing my whole damn site to 777 at one point to test.
I strongly believe there is something wrong with the plugin.