$xwiki not always available?

Hi! I've made a panel that displays tags in a tag cloud (size relative to occurrence). But on a few occasions I get an exception, and I've managed to pinpoint fairly accurately under what circumstance. The code involved, that usually works is this: #set($query = "select elements(prop.list) from BaseObject as obj, DBStringListProperty as prop where obj.className='XWiki.TagClass' and obj.id=prop.id.id and prop.id.name='tags'") #set( $allTags = $xwiki.search($query)) #set( $allTagsSorted = $xwiki.sort($allTags)) If the user is not logged in, and presses the login link in the top left corner (--> /xwiki/bin/login/XWiki/XWikiLogin), the panel returns the enclosed exception. After some debugging, it seems that $allTags is not assigned a value from $xwiki.search($query). This leads me to believe that $xwiki might not be available from this particular context. Has anyone else encountered this, or is it an artifact in my environment? I'm running xwiki v1.1-milestone2, mysql, winxp, tomcat, java5. Both my db and xwiki installs are pretty fresh and un-tampered with. best regards :-) Thomas 13:47:50,211 ERROR http-9080-2 http://myHost:9080/xwiki/bin/login/XWiki/XWikiLogin?xredirect=http%3A%2F%2F… SimpleLog4JLogSystem:logVelocityMessage:154 - Method sort threw exception for reference $xwiki in template XWiki.XWikiLogin at [6,24] org.apache.velocity.exception.MethodInvocationException: Invocation of method 'sort' in class com.xpn.xwiki.api.XWiki threw exception java.lang.NullPointerException @ XWiki.XWikiLogin[6,31] at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:286) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203) at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:419) at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:73) at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:125) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143) at com.xpn.xwiki.render.XWikiVelocityRenderer.render(XWikiVelocityRenderer.java:91) at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:229) at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:161) at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:132) at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:366) at com.xpn.xwiki.objects.classes.TextAreaClass.displayView(TextAreaClass.java:165) at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:1265) at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:1245) at com.xpn.xwiki.api.Document.display(Document.java:864) at sun.reflect.GeneratedMethodAccessor90.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:245) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:107) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:88) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:194) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74) at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:448) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:88) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1249) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1218) at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:491) at sun.reflect.GeneratedMethodAccessor59.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:245) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:194) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1249) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1218) at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:491) at sun.reflect.GeneratedMethodAccessor59.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:245) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:194) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:107) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1249) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1218) at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:98) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:159) at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414) at javax.servlet.http.HttpServlet.service(HttpServlet.java:690) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:118) 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:228) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:216) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:634) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:445) at java.lang.Thread.run(Thread.java:595) Caused by: java.lang.NullPointerException at java.util.Collections.sort(Collections.java:116) at com.xpn.xwiki.api.XWiki.sort(XWiki.java:1676) at sun.reflect.GeneratedMethodAccessor110.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:245) ... 99 more