the XML response that was returned from the server is invalid,该怎么解决

the XML response that was returned from the server is invalid
PHP中出现的。
首先声明不是编码的问题，全部是英文，全部是utf8，没有涉及到中文。

[解决办法]
是从SERVER返回的XML有问题吧,在SERVER保存看下~~?
[解决办法]
我支持qqhe325() 的看法
[解决办法]
不支持白键