Warning: session_start(): Cannot send session cache limiter - headers already sent ...

this kind of errors would occur, when the encoding of your script file needs to send some headers just after your script starts to execute,

this happens mostly with the scripts using normal utf8 encoding.

To overcome the issue, use utf8(without BOM) encoding provided by notepad++ and most modern editors. Using utf8 encoding and cookie based sessions, will result in headers already sent by error.