Warning: session_start(): Cannot ... ...headers already sent by

Apologies in advance if this query has already been answered. I have searched the posts, and have found similar questions, but no answers that seem to help me.

I've just installed drupal 4.4.0 on my ISP (running Apache 1.3.29 PHP 4.3.4 and MySQL 4.0.18)

The initial Drupal webpage is loaded, along with the following errors

Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /home/okayam2/public_html/includes/conf.php:70) in /home/okayam2/public_html/includes/session.inc on line 5

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home/okayam2/public_html/includes/conf.php:70) in /home/okayam2/public_html/includes/session.inc on line 5

warning: Cannot modify header information - headers already sent by (output started at /home/okayam2/public_html/includes/conf.php:70) in /home/okayam2/public_html/includes/common.inc on line 1233.

due to the nature of my ISP, my drupal database is called okayam2_drupal. (I can't login in and create databases through phpmyadmin, have to create through the isp's MySQL database Admin Panel)

can anyone point me in the right direction here to fix this. First CMS site.

I have edited conf.php like;
# $db_url = "mysql://user:password@hostname/database";
# $db_url = "pgsql://user:password@hostname/database";
$db_url = "mysql://user:password@localhost/okayam2_drupal";

Thanks in advance