Cannot Login to TeamCity 5 from Idea 11.1.1

I'm having problems logging in to Teamcity 5 from Idea 11.1.1. The version of the teamcity plugin is 5.13430, the version of Teamcity is TeamCity Enterprise 5.1.2 (build 13430)

The Idea log states:-

2012-05-09 15:39:35,336 [  24701]  ERROR - tartup.impl.StartupManagerImpl - Original exception:  
java.lang.ClassNotFoundException: com.intellij.ui.TreeToolTipHandler PluginClassLoader[Jetbrains TeamCity Plugin, 5.13430]
 at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:77)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
 at jetbrains.buildServer.tree.AbstractStatusTree.<init>(AbstractStatusTree.java:85)
 at jetbrains.buildServer.tree.projectsTree.ProjectStatusTree.<init>(ProjectStatusTree.java:32)
 at jetbrains.buildServer.tree.StatusComponent.createProjectsTree(StatusComponent.java:159)
 at jetbrains.buildServer.tree.StatusComponent.createTrees(StatusComponent.java:154)
 at jetbrains.buildServer.tree.StatusComponent.<init>(StatusComponent.java:66)
 at jetbrains.buildServer.statusBar.StatusBarNotificationManager.<init>(StatusBarNotificationManager.java:117)
 at jetbrains.buildServer.BuildServerManager$1.run(BuildServerManager.java:110)
 at com.intellij.ide.startup.impl.StartupManagerImpl.a(StartupManagerImpl.java:203)
 at com.intellij.ide.startup.impl.StartupManagerImpl.access$100(StartupManagerImpl.java:41)
 at com.intellij.ide.startup.impl.StartupManagerImpl$4.run(StartupManagerImpl.java:170)
 at com.intellij.openapi.project.DumbServiceImpl.a(DumbServiceImpl.java:213)
 at com.intellij.openapi.project.DumbServiceImpl.access$1000(DumbServiceImpl.java:51)
 at com.intellij.openapi.project.DumbServiceImpl$IndexUpdateRunnable$1$3.run(DumbServiceImpl.java:359)
 at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
 at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:646)
 at java.awt.EventQueue.access$000(EventQueue.java:84)
 at java.awt.EventQueue$1.run(EventQueue.java:607)
 at java.awt.EventQueue$1.run(EventQueue.java:605)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
 at java.awt.EventQueue.dispatchEvent(EventQueue.java:616)
 at com.intellij.ide.IdeEventQueue.e(IdeEventQueue.java:699)
 at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:538)
 at com.intellij.ide.IdeEventQueue.b(IdeEventQueue.java:420)
 at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:378)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
 at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
 at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)