You need to add a query cache value to your my.cnf file. What type of database are you using: innodb, myISAM, etc. Also what access do you have to your server. You need root access to edit my.cnf, or administrator rights for windows.
No idea. As reported by phpMyAdmin's Server variables and settings page: storage engine: MyISAM (and many other instances of string "MyISAM") but have innodb YES (and many other instances of string "innodb") I do have root access. It's my VPS. Thanks jestep.