[VE][338] Error Message Feedback

Hello,

I don´t undestand this error because i´ve a php code who generate a
PHPSESSID (with a session_start() wich i need):

Line 47, column 70: cannot generate system identifier for general entity
"PHPSESSID"

....confidencial/noticia.php?noticia=331&PHPSESSID=96a721ba8d86aa0669057712e7
ebb1 


How i could get a valid XHTML4.0 transitional?

Thank you very much!

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