Ok, WP-Cache activated, gz output deactivated and .. no output in the options->WP-Cache. After searching a while I found this error
Fatal error: Call to undefined function readlink() in C:\xampp\htdocs\mywp\blog\wp-content\plugins\wp-cache\wp-cache.php on line 541
Ok, readlink is a linux/unix command isn't it? So you probarly want
1) Modify and support windows
2) Try and Catch readlink (NO @readlink please) and output the user it's linux/unix only. In any case, give an output! Don't use the @ sign cause it took me nearly an hour to find the problem.
Aww sry, tried replying to WP-Cache plugin. Sorry to mess things up again.