Error QCodo Session_Start()

Hello all, I have a mystery problem with session_start, but when I modify something the page with error session_start and relaunch the error desapear don't know why ???

session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cache limiter - headers already sent (output started at /Users/mbagiella/Sites/contographie8/web/pages/InsertConte.form.php:1)
Error Type:   E_WARNING    

Source File:   /Users/mbagiella/Sites/contographie8/qcodo/wwwroot/includes/prepend.inc.php         Line:   103    

Line 98:    
Line 99:            
Line 100:            /////////////////////////////
Line 101:            // Start Session Handler (if required)
Line 102:            /////////////////////////////
Line 103:            session_start();
Line 104:    
Line 105:            //////////////////////////////////////////////
Line 106:            // Setup Internationalization and Localization (if applicable)
Line 107:            // Note, this is where you would implement code to do Language Setting discovery, as well, for example:
Line 108:            // * Checking against $_GET['language_code']

or your file is in UTF with bom

http://en.wikipedia.org/wiki/Byte_order_mark

Basically its something you most likely get for using notepad on windows to edit you php files.

It should be harmless but php chokes on it.

Notepad++ can display if your file has bom.