Stage plugin fails with ClassCastException

[ERROR] FATAL ERROR
[INFO] ------------------------------------------------------------------------
[INFO] org.apache.maven.wagon.providers.ssh.jsch.ScpWagon
[INFO] ------------------------------------------------------------------------
[INFO] Trace
java.lang.ClassCastException: org.apache.maven.wagon.providers.ssh.jsch.ScpWagon
at org.apache.maven.plugins.stage.DefaultRepositoryCopier.copy(DefaultRepositoryCopier.java:252)
at org.apache.maven.plugins.stage.CopyRepositoryMojo.execute(CopyRepositoryMojo.java:93)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:451)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:558)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:512)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:482)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:330)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:227)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:142)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:336)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:129)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:287)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 49 seconds
[INFO] Finished at: Wed Dec 10 22:13:24 EST 2008
[INFO] Final Memory: 3M/6M
[INFO] ------------------------------------------------------------------------
/Users/benson/xmlschema

mvn stage:copy \
-Dsource="http://people.apache.org/~bimargulies/maven_staging" \
-Dtarget="scp://people.apache.org/www/people.apache.org/repo/m2-ibiblio-rsync-repository" \
-Dversion=1.4.3 \
-DtargetRepositoryId=apache.releases

<servers>
<server>
<id>apache-repo</id>
<username>bimargulies</username>
</server>
<server>
<id>apache.releases</id>
<username>bimargulies</username>
</server>
<server>
<id>apache-snapshots</id>
<username>bimargulies</username>
</server>
</servers>