Sessions - session_start()

Hi, I've been building a site with PHP 5 on my develop machine. I've been woring alot with session handling. For example I've been using session_start() now and then depending on where the user/vistor are or are doing. But now I've moved the site to a host server with PHP 4.3.8 and now I keep getting error messages all the time where I use session_start(). The error message looks like this: Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /var/www/html/index.php:9) in /var/www/html/index.php on line 82 But I found out that if I put the tag in the absolute top of every page it seems to work. But then I need to do alot of changes on all the pages. Does anyone know if there's any workaround for this? Thanks in advance // Jonas