I'm using jenkins 1.466.2 via the regular Ubuntu packages on Ubuntu Quantla (12.10) with the copyArtifact plugin (version 1.25)

The console output for the build of one of my Jenkins projects consistently shows this:

Started by user Murray Cumming
Building in workspace /var/lib/jenkins/workspace/maliit-plugins
Checkout:maliit-plugins / /var/lib/jenkins/workspace/maliit-plugins - hudson.remoting.LocalChannel@35e47b48
Using strategy: Default
Last Built Revision: Revision 1004cc39badd17308a1fabfe0b72d1e762572b4b (origin/master)
Fetching changes from 1 remote Git repository
Fetching upstream changes from git://gitorious.org/maliit/maliit-plugins.git
Commencing build of Revision 1004cc39badd17308a1fabfe0b72d1e762572b4b (origin/master)
Checking out Revision 1004cc39badd17308a1fabfe0b72d1e762572b4b (origin/master)
FATAL: hudson/maven/MavenModuleSetBuild
java.lang.NoClassDefFoundError: hudson/maven/MavenModuleSetBuild
at hudson.plugins.copyartifact.CopyArtifact.perform(CopyArtifact.java:198)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:710)
at hudson.model.Build$RunnerImpl.build(Build.java:178)
at hudson.model.Build$RunnerImpl.doRun(Build.java:139)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:480)
at hudson.model.Run.run(Run.java:1438)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:239)
Caused by: java.lang.ClassNotFoundException: hudson.maven.MavenModuleSetBuild
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 10 more