WP Super Cache plugin activation problem

I am trying to activate (WP Super Cache – Version 0.9.8 – latest version) plugin under WordPress 2.9

First I got the message (Warning! PHP Safe Mode Enabled!), so I disabled safe_mode in php.ini and restarted the server

Also the message said (Error: Your cache directory (/httpdocs/wp-content/cache/) or /httpdocs/wp-content need to be writable for this plugin to work. Double-check it.)

So I chmod both folders to 777, but up to this moment I can’t activate the plugin and I still get the same warning message ??

So can someone please help me please by telling me what I am missing here? and how I can activate this plugin?

Thanks in advance for your time