Griffon wrapper does not work on plugin projects

./griffonw clean
Welcome to Griffon 0.9.5-rc2 - http://griffon.codehaus.org/
Licensed under Apache Standard License 2.0
Griffon home is set to: /Users/aalmiray/.griffon/wrapper/dists/griffon-0.9.5-rc2

Base Directory: /private/tmp/foo
Running script /Users/aalmiray/.griffon/wrapper/dists/griffon-0.9.5-rc2/scripts/Clean.groovy
Resolving dependencies...
Dependencies resolved in 729ms.
Environment set to development
Resolving plugin dependencies ...
java.lang.ClassNotFoundException: FooGriffonPlugin
	at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:391)
	at gant.Gant$_dispatch_closure6.doCall(Gant.groovy:407)
	at gant.Gant$_dispatch_closure6.doCall(Gant.groovy)
	at java_util_concurrent_Callable$call.call(Unknown Source)
	at gant.Gant.withBuildListeners(Gant.groovy:427)
	at gant.Gant.this$2$withBuildListeners(Gant.groovy)
	at gant.Gant$this$2$withBuildListeners.callCurrent(Unknown Source)
	at gant.Gant.dispatch(Gant.groovy:405)
	at gant.Gant.this$2$dispatch(Gant.groovy)
	at gant.Gant.invokeMethod(Gant.groovy)
	at gant.Gant.executeTargets(Gant.groovy:591)
	at org.codehaus.griffon.cli.GriffonScriptRunner$GantCustomizer.prepareTargets(GriffonScriptRunner.java:928)
	at org.codehaus.griffon.cli.GriffonScriptRunner.executeWithGantInstance(GriffonScriptRunner.java:634)
	at org.codehaus.griffon.cli.GriffonScriptRunner.executeWithGantInstanceNoException(GriffonScriptRunner.java:654)
	at org.codehaus.griffon.cli.GriffonScriptRunner.callPluginOrGriffonScript(GriffonScriptRunner.java:384)
	at org.codehaus.griffon.cli.GriffonScriptRunner.doExecuteCommand(GriffonScriptRunner.java:297)
	at org.codehaus.griffon.cli.GriffonScriptRunner.main(GriffonScriptRunner.java:142)
	at org.codehaus.griffon.cli.support.GriffonStarter.rootLoader(GriffonStarter.java:198)
	at org.codehaus.griffon.cli.support.GriffonStarter.main(GriffonStarter.java:223)
	at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:66)
	at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:124)
	at org.gradle.wrapper.GriffonWrapperMain.main(GriffonWrapperMain.java:60)
Caused by: java.lang.ClassNotFoundException: FooGriffonPlugin
	at java_lang_ClassLoader$loadClass.call(Unknown Source)
	at org.codehaus.griffon.artifacts.ArtifactInstallEngine.resolvePluginDependencies(ArtifactInstallEngine.groovy:91)
	at org.codehaus.griffon.artifacts.ArtifactInstallEngine$resolvePluginDependencies.call(Unknown Source)
	at _GriffonSettings$_run_closure1.doCall(_GriffonSettings:41)
	at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
	at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
	at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy:185)
	at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy)
	at java_util_concurrent_Callable$call.call(Unknown Source)
	at org.codehaus.gant.GantBinding.withTargetEvent(GantBinding.groovy:90)
	at org.codehaus.gant.GantBinding.this$4$withTargetEvent(GantBinding.groovy)
	at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy:185)
	at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy)
	at java_util_concurrent_Callable$call.call(Unknown Source)
	at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
	... 21 more