php java_require No such file or directory问题

调用java_require("D:/wamp/www/uibp/jar/properties.jar");
D:/wamp/www/uibp/jar/properties.jar 这个文件是存在的。为什么报错：

Could not open jar file D:/wamp/www/uibp/jar/properties.jar, reason: D:/wamp/www/uibp/jar/properties.jar (No such file or directory)

求大神解释！