Below are the error in php due to session. This happens usually when server is unable to save the sessions data temporarily due to the improper path settings in session.save_path = “\xampp\tmp”.
Solution is to set the session.savepath correctly to point to directory where server can find it easily.

[php]
Warning: session_start() [function.session-start]: open(\xampp\tmp\sess_nsvvoh9f5l55g063d7qka1lq72, O_RDWR) failed: No such file or directory (2) in D:\htdocs\bull_ext\access_control\main.inc on line 39

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at D:\htdocs\bull_ext\access_control\main.inc:39) in D:\htdocs\bull_ext\access_control\main.inc on line 39

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at D:\htdocs\bull_ext\access_control\main.inc:39) in D:\htdocs\bull_ext\access_control\main.inc on line 39

Warning: Cannot modify header information – headers already sent by (output started at D:\htdocs\bull_ext\access_control\main.inc:39) in D:\htdocs\bull3\framework\application.inc on line 589

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This settings is stored inside the php.ini file, which can be found under c:\xampp\php\ directory.

First stop the Xampp Server.

[php]
session.save_path = "\xampp\tmp"
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and change it to look like this

[php]
session.save_path = "C:\xampp\tmp"
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Restart the Xampp Server. That’s it now your session should work as expected.

Hope this was useful for someone.