java调用dll的问题，请教！！！

[hzpike]

调用某个dll（下载的应该不会错）中的函数SendSms（），
JavaSms MyDLL = new JavaSms();
Result = MyDLL.SendSms（);
出现如下错误
java.lang.UnsatisfiedLinkError: SendSms
at sms.JavaSms.SendSms(Native Method)
at _jsp._sms__jsp._jspService(/sms.jsp:12)
at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
at com.caucho.jsp.Page.pageservice(Page.java:571)
at com.caucho.server.dispatch.PageFilterChain.doFilter(PageFilterChain.java:155)
at com.caucho.server.cache.CacheFilterChain.doFilter(CacheFilterChain.java:214)
at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:177)
at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:221)
at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:263)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:333)
at com.caucho.util.ThreadPool.runTasks(ThreadPool.java:464)
at com.caucho.util.ThreadPool.run(ThreadPool.java:408)
at java.lang.Thread.run(Thread.java:534)
请问是什么原因，如何解决

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