After adding new IP range for discovery, I click on Save and Restart Discovery button, I get an "Unexpected Error":

The OpenNMS Web User Interface Has Experienced an Error

The OpenNMS web UI has encountered an error that it does not know how to handle.

Possible causes could be that the database is not responding, the OpenNMS application has stopped or is not running, or there is an issue with the servlet container.

Please bring this message to the attention of the person responsible for maintaining OpenNMS for your organization, and have him or her check that OpenNMS, the external servlet container (if applicable), and the database are all running without errors.

Please take a few moments to include a description of what you were doing when you encountered this problem. Without knowing the context of the error, it's often difficult for the person looking at the problem to narrow the range of possible causes. Bug reports that do not include any information on the context in which the problem occurred will receive a lower priority and may even be closed as invalid.

System Details
-------------- OpenNMS Version: 1.10.12
Java Version: 1.7.0_25 Oracle Corporation
Java Virtual Machine: 23.25-b01 Oracle Corporation
Operating System: Windows 7 6.1 amd64
Servlet Container: jetty/7.5.1.v20110908 (Servlet Spec 2.5)
User Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)

Request Details
--------------- Locale: en_US
Method: POST
Path Info: null
Path Info (translated): null
Protocol: HTTP/1.1
URI: /opennms/errors/unknownexception.jsp
URL: http://localhost:8980/opennms/errors/unknownexception.jsp
Scheme: http
Server Name: localhost
Server Port: 8980

Exception Stack Trace
--------------------- java.io.FileNotFoundException
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:212)
at java.io.FileOutputStream.<init>(FileOutputStream.java:165)
at org.opennms.netmgt.config.DiscoveryConfigFactory.saveXml(DiscoveryConfigFactory.java:234)
at org.opennms.netmgt.config.DiscoveryConfigFactory.saveConfiguration(DiscoveryConfigFactory.java:261)
at org.opennms.web.admin.discovery.ActionDiscoveryServlet.doPost(ActionDiscoveryServlet.java:232)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:547)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1355)
at org.extremecomponents.table.filter.AbstractExportFilter.doFilter(AbstractExportFilter.java:49)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1326)
at org.opennms.web.StoreRequestPropertiesFilter.doFilter(StoreRequestPropertiesFilter.java:77)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1326)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:399)
at org.opennms.web.springframework.security.AuthFilterEnabler.doFilterHttp(AuthFilterEnabler.java:100)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.ui.SessionFixationProtectionFilter.doFilterHttp(SessionFixationProtectionFilter.java:67)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.ui.ExceptionTranslationFilter.doFilterHttp(ExceptionTranslationFilter.java:101)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.providers.anonymous.AnonymousProcessingFilter.doFilterHttp(AnonymousProcessingFilter.java:105)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.wrapper.SecurityContextHolderAwareRequestFilter.doFilterHttp(SecurityContextHolderAwareRequestFilter.java:91)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.ui.basicauth.BasicProcessingFilter.doFilterHttp(BasicProcessingFilter.java:174)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.ui.AbstractProcessingFilter.doFilterHttp(AbstractProcessingFilter.java:278)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.ui.logout.LogoutFilter.doFilterHttp(LogoutFilter.java:89)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.context.HttpSessionContextIntegrationFilter.doFilterHttp(HttpSessionContextIntegrationFilter.java:235)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:411)
at org.springframework.security.util.FilterChainProxy.doFilter(FilterChainProxy.java:188)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1326)
at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1326)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:479)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:520)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:940)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:409)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:874)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110)
at org.eclipse.jetty.server.Server.handle(Server.java:349)
at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:441)
at org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:921)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:784)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:223)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:46)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:545)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:43)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:598)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:533)
at java.lang.Thread.run(Thread.java:724)