急：求助sniffer 不能使用。。。

装完后老是提示：
This Sniffer Portable software is not licensed for the function you are trying
to access,Please contact a Network Associates(www.nai.com)
sales representative to purchase other Topplogy support.
然后反复注册，不让用。为什么啊？
跪求各位大侠帮忙啊～～～～～