Fatal error

when i was installing wp 1.2 mingus to server, en error came in like this:
Fatal error: Call to a member function on a non-object in
/home/xxxxxxx/subdomain/blog.xxxxxx.net/wp-admin/install.php on
line 52
here is the 52nd line:
$wpdb->hide_errors();
what should i do?
thx,
lesti