Cannot send session cookie

Folks I am a new to php. I am currently learning about session handling and would appreciate some assistance with the following: I am using php 4.3.7 and I am using the default values in the php.ini for session.use_cookies = 1 session.cache_limiter = nocache When experimenting with a few simple lines of code <script language='php'> ---- This is line 14 session_start(); </script> I get the following errors: Warning: session_start(): Cannot send session cookie - headers already sent by (output started at e:\http\cgi\a.php:14) in e:\http\cgi\a.php on line 15 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at e:\http\cgi\a.php:14) in e:\http\cgi\a.php on line 15 Can anyone offer me a insight on the reason for the error. Mike