php json解析问题

{"FUID":"1344570006238357","photourl":"http://xxx.xxxx.com/xxxx/1344570010816293.png","NickName":"123456","Content":"<img src="../Expression/ali/ali11.gif" class="editorimg"><img src="../Expression/ali/ali24.gif" class="editorimg"><img src="../Expression/ali/ali25.gif" class="editorimg"><img src="../Expression/ali/ali42.gif" class="editorimg">","rtime":"2012-08-19 16:16:07"}
转换成json时,是没有问题的,但是转换回来就会出错,只要里面出现Content这种内容就转换不回来?