database caching error with query using LIKE

[eluser]dardar[/eluser]
Everything is OK with codeigniter, just if I enable database query caching it returns blank screen:

Code:

$db['default']['cache_on'] = TRUE;
$db['default']['cachedir'] = "cache";

Maybe it's only server fault?

I'm using USB webserver, windows xp 64 OS, from http://www.usbwebserver.nl/ (you can test with it easaly - it's complete portablewebserver)