initial installation base_url problem

Hi I'm installing on a subdomain in a ensim server,

due some problem the install fails
if I point to my website i get http://site.com/var/subdomain/lala/html/install.php

if I create manual the settings.php with only $base_url inside I can get to the install

after creating the DB it fails again and I need to set the base_url again in the settings.php (bacause its overwritten by install)

but then I get

    * user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY fit DESC LIMIT 0, 1' at line 1 query: SELECT * FROM menu_router WHERE path IN () ORDER BY fit DESC LIMIT 0, 1 in /var/www/mario/includes/menu.inc on line 315.
    * user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY fit DESC LIMIT 0, 1' at line 1 query: SELECT * FROM menu_router WHERE path IN () ORDER BY fit DESC LIMIT 0, 1 in /var/www/mario/includes/menu.inc on line 315.

I guess I'm missing somthing for the base_url for installation and the error of mysql

I'm using drupal-6.1.tar.gz as start