Your webhosting has to fulfill certain parameters for the installation and proper functioning of Drupal. You can find the updated overview on the Drupal.org site (http://drupal.org/requirements).

Examples of Czech webhostings which support Drupal:
Anima Webhosting
C4 webhosting
Inhosting.cz
Klenot.cz
Lives.cz
Zserver.cz

In Slovakia you can try, for example:
Armin.sk

On the contrary, you can find a “black list” of webhostings that don´t support Drupal here on the Drupal.cz site.