VelocityViewServlet : Error processing a template for path '/pages/vercoleccionfeed.html'

Invocation of method 'render' in class net.universia.commons.velocity.tools.FeedTool threw exception com.sun.syndication.io.FeedException: Invalid rss_1.0 feed, missing item title at VM_global_library.vm[line 658, column 6]
com.sun.syndication.io.FeedException: Invalid rss_1.0 feed, missing item title
	at com.sun.syndication.io.impl.RSS090Generator.checkNotNullAndLength(RSS090Generator.java:128)
	at com.sun.syndication.io.impl.RSS10Generator.checkItemConstraints(RSS10Generator.java:121)
	at com.sun.syndication.io.impl.RSS090Generator.addItem(RSS090Generator.java:217)
	at com.sun.syndication.io.impl.RSS090Generator.addItems(RSS090Generator.java:209)
	at com.sun.syndication.io.impl.RSS090Generator.populateFeed(RSS090Generator.java:90)
	at com.sun.syndication.io.impl.RSS090Generator.generate(RSS090Generator.java:56)
	at com.sun.syndication.io.WireFeedOutput.outputJDom(WireFeedOutput.java:207)
	at com.sun.syndication.io.WireFeedOutput.output(WireFeedOutput.java:147)
	at com.sun.syndication.io.SyndFeedOutput.output(SyndFeedOutput.java:97)
	at net.universia.rayuela.feed.Feed.render(Feed.java:210)
	at net.universia.rayuela.feed.Feed.render(Feed.java:216)
	at net.universia.commons.velocity.tools.FeedTool.render(FeedTool.java:141)
	at sun.reflect.GeneratedMethodAccessor290.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:389)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:378)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:270)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:262)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:342)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:212)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:247)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
	at org.apache.velocity.Template.merge(Template.java:328)
	at org.apache.velocity.Template.merge(Template.java:235)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.performMerge(VelocityViewServlet.java:805)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.mergeTemplate(VelocityViewServlet.java:762)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doRequest(VelocityViewServlet.java:555)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doGet(VelocityViewServlet.java:509)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:114)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:91)
	at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)
	at com.caucho.server.webapp.DispatchFilterChain.doFilter(DispatchFilterChain.java:97)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:266)
	at com.caucho.server.webapp.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:283)
	at com.caucho.server.webapp.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:108)
	at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1078)
	at org.apache.struts.tiles.TilesRequestProcessor.doForward(TilesRequestProcessor.java:295)
	at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:396)
	at org.apache.struts.tiles.TilesRequestProcessor.processForwardConfig(TilesRequestProcessor.java:347)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:232)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:114)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:91)
	at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)
	at com.caucho.server.cache.CacheFilterChain.doFilter(CacheFilterChain.java:194)
	at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:187)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:266)
	at com.caucho.server.hmux.HmuxRequest.handleRequest(HmuxRequest.java:435)
	at com.caucho.server.port.TcpConnection.run(TcpConnection.java:678)
	at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:721)
	at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:643)
	at java.lang.Thread.run(Thread.java:619)