Using the Parameterized Trigger Plugin will cause this Stacktrace in the
logfile. The builds won't get triggered.

Feb 19, 2009 2:29:35 PM hudson.model.Executor run
SEVERE: Executor throw an exception unexpectedly
java.lang.NoClassDefFoundError: hudson/model/ParameterizedProjectTask
at
hudson.plugins.parameterizedtrigger.FileBuildTriggerConfig.trigger(FileBuildTriggerConfig.java:77)
at
hudson.plugins.parameterizedtrigger.BuildTrigger.perform(BuildTrigger.java:40)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:365)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:353)
at hudson.model.Build$RunnerImpl.cleanUp(Build.java:174)
at hudson.model.Run.run(Run.java:933)
at hudson.model.Build.run(Build.java:112)
at hudson.model.ResourceController.execute(ResourceController.java:93)
at hudson.model.Executor.run(Executor.java:119)