Index: trunk/core/kernel/session/session.php
===================================================================
diff -u -r1852 -r1860
--- trunk/core/kernel/session/session.php	(.../session.php)	(revision 1852)
+++ trunk/core/kernel/session/session.php	(.../session.php)	(revision 1860)
@@ -285,7 +285,7 @@
 		
 		$tmp_sid = $this->GetPassedSIDValue();
 
-		if( !defined('IS_INSTALL') && IS_INSTALL )
+		if( !(defined('IS_INSTALL') && IS_INSTALL) )
 		{
 			$expired_sids = $this->DeleteExpired();
 			if( ( $expired_sids && in_array($tmp_sid,$expired_sids) ) || ( $tmp_sid && !$this->Check() )  )