Exception error when logging

hello,

when I enter the User and Password in the login screen openfire, displays theexception error below, anyone know what might be?

thanks

java.lang.NoClassDefFoundError: Could not initialize class org.jivesoftware.admin.LoginLimitManager$LoginLimitManagerContainer

at org.jivesoftware.admin.LoginLimitManager.getInstance(LoginLimitManager.java:38)

at org.jivesoftware.openfire.admin.login_jsp._jspService(login_jsp.java:143)

at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)

at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1093)

at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:39)

at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1084)

at org.jivesoftware.util.LocaleFilter.doFilter(LocaleFilter.java:66)

at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1084)

at org.jivesoftware.util.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingF ilter.java:42)

at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1084)

at org.jivesoftware.admin.PluginFilter.doFilter(PluginFilter.java:70)

at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1084)

at org.jivesoftware.admin.AuthCheckFilter.doFilter(AuthCheckFilter.java:146)

at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1084)

at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)

at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)

at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)

at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)

at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)

at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollect ion.java:206)

at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)

at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)

at org.mortbay.jetty.Server.handle(Server.java:324)

at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)

at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843 )

at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:648)

at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)

at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)

at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)

at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)