Multiple IDE fatal errors on Idea 12.1.8 Ultimate

[mikolajr]

Current plugin causes instant IDe fatal errors on Idea Ultimate 12.1.8.
What is interesting, plugin works, ignore functionality works as expected (at least for Git, I do not use any other SCMs).
Sample stacktrace:

mobi.hsz.idea.gitignore.outer.OuterIgnoreLoaderComponent@a7fa72: com.intellij.util.containers.ContainerUtil.getFirstItem(Ljava/util/List;)Ljava/lang/Object;
java.lang.NoSuchMethodError: com.intellij.util.containers.ContainerUtil.getFirstItem(Ljava/util/List;)Ljava/lang/Object;
    at mobi.hsz.idea.gitignore.util.exec.ExternalExec.runForSingle(ExternalExec.java:130)
    at mobi.hsz.idea.gitignore.util.exec.ExternalExec.getGitExcludesFile(ExternalExec.java:79)
    at mobi.hsz.idea.gitignore.lang.kind.GitLanguage$1.fetch(GitLanguage.java:57)
    at mobi.hsz.idea.gitignore.outer.OuterIgnoreLoaderComponent.projectOpened(OuterIgnoreLoaderComponent.java:108)
    at com.intellij.openapi.project.impl.ProjectImpl.c(ProjectImpl.java:418)
    at com.intellij.openapi.project.impl.ProjectImpl.access$200(ProjectImpl.java:76)
    at com.intellij.openapi.project.impl.ProjectImpl$MyProjectManagerListener.projectOpened(ProjectImpl.java:454)
    at com.intellij.openapi.project.impl.ProjectManagerImpl$2.projectOpened(ProjectManagerImpl.java:155)
    at com.intellij.openapi.project.impl.ProjectManagerImpl.e(ProjectManagerImpl.java:1041)
    at com.intellij.openapi.project.impl.ProjectManagerImpl.openProject(ProjectManagerImpl.java:411)
    at com.intellij.openapi.project.impl.ProjectManagerImpl.loadAndOpenProject(ProjectManagerImpl.java:502)
    at com.intellij.ide.impl.ProjectUtil.openProject(ProjectUtil.java:187)
    at com.intellij.ide.RecentProjectsManager.doOpenProject(RecentProjectsManager.java:46)
    at com.intellij.ide.RecentProjectsManagerBase$MyAppLifecycleListener.appStarting(RecentProjectsManagerBase.java:326)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.util.messages.impl.MessageBusConnectionImpl.deliverMessage(MessageBusConnectionImpl.java:120)
    at com.intellij.util.messages.impl.MessageBusImpl.doPumpMessages(MessageBusImpl.java:228)
    at com.intellij.util.messages.impl.MessageBusImpl.pumpMessages(MessageBusImpl.java:219)
    at com.intellij.util.messages.impl.MessageBusImpl.sendMessage(MessageBusImpl.java:209)
    at com.intellij.util.messages.impl.MessageBusImpl.access$000(MessageBusImpl.java:43)
    at com.intellij.util.messages.impl.MessageBusImpl$1.invoke(MessageBusImpl.java:131)
    at com.sun.proxy.$Proxy35.appStarting(Unknown Source)
    at com.intellij.idea.IdeaApplication.d(IdeaApplication.java:349)
    at com.intellij.idea.IdeaApplication.access$500(IdeaApplication.java:57)
    at com.intellij.idea.IdeaApplication$IdeStarter$2.run(IdeaApplication.java:316)
    at com.intellij.openapi.application.impl.LaterInvocator$FlushQueue.run(LaterInvocator.java:343)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
    at com.intellij.ide.IdeEventQueue.d(IdeEventQueue.java:700)
    at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:525)
    at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:348)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)