Cannot send session cache limiter - headers already sent

Hello,

I am trying to install emoncms on a shared webhosting at one.com.
I'm having some session problems with emoncms that are hard to troubleshoot;

I'm stuck with this error at the login page.

in /customers/f/b/1/vanlanduytvleeswaren.be/httpd.www/Celsius/Modules/log/EmonLogger.php on line 28 Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /customers/f/b/1/vanlanduytvleeswaren.be/httpd.www/Celsius/Modules/log/EmonLogger.php:28) in /customers/f/b/1/vanlanduytvleeswaren.be/httpd.www/Celsius/Modules/user/user_model.php on line 103 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /customers/f/b/1/vanlanduytvleeswaren.be/httpd.www/Celsius/Modules/log/EmonLogger.php:28) in /customers/f/b/1/vanlanduytvleeswaren.be/httpd.www/Celsius/Modules/user/user_model.php on line 103

Thanks in advance,