Error after Installing CiviCRM 4.6.4 on Drupal 6, drupal attempts to reinstall at localhost/drupal
Unless there is a good reason why you have chosen to use Drupal 6, I would suggest that you use Drupal 7 instead.  As Laryn points out Drupal will reach end of life soon.  Things are more likely to go smoothly if you are using Drupal 7 and you also find it easier to get help.

I would also recommend that you use the latest version of CiviCRM - currently 4.6.12 (or 4.7.1).