Error de Variable de SESSION PHP

[G93]

que significa este error?


Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at C:\AppServ\www\Login\perfil.php:1) in C:\AppServ\www\Login\validarUsuario.php on line 2

[cell001]

checa esto, GatorV muestra una solución [URL="http://www.forosdelweb.com/f18/clasico-error-session-start-cannot-send-session-cache-limiter-headers-alredy-sent-696091/"]Link/[/URL]

O este [URL="http://www.comunidadhosting.com/t/warning-session_start-cannot-send-session-cache-limiter-headers-already-sent.1656/#.UrJnqNxqCSo"]Link[/URL]

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