调用常量的问题

调用常量时遇到：

Warning: require(ROOT_PATHincludes/title.inc.php) [function.require]: failed to open stream: No such file or directory in C:\AppServ\www\TestGuest0.5\register.php on line 10

Fatal error: require() [function.require]: Failed opening required 'ROOT_PATHincludes/title.inc.php' (include_path='.;C:\php5\pear') in C:\AppServ\www\TestGuest0.5\register.php on line 10

echo发现常量没解析，问题出在常量声明在常量调用之后，使用了require刚开始没发现。