Servlet /52nSOSv3.5.0 threw load() exception求解

使用52north SOS，出现下面错误！求指教！！！
信息: Deploying web application archive 52nSOSv3.5.0.war
2013-9-18 9:54:21 org.apache.catalina.core.ApplicationContext log
信息: Marking servlet SOS as unavailable
2013-9-18 9:54:21 org.apache.catalina.core.StandardContext loadOnStartup
严重: Servlet /52nSOSv3.5.0 threw load() exception
javax.servlet.UnavailableException
at org.n52.sos.SOS.init(SOS.java:128)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1206)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1026)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4421)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4734)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:943)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:563)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1399)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:297)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(Unknown Source)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(Unknown Source)
at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1500)
at org.apache.catalina.manager.HTMLManagerServlet.doPost(HTMLManagerServlet.java:252)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.filters.CsrfPreventionFilter.doFilter(CsrfPreventionFilter.java:194)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)