Startup error: Unable to deploy plugin 'null' causes Confluence to start with plugins not being started properly

2011-01-07 10:29:45,113 ERROR [main] [atlassian.plugin.loaders.ScanningPluginLoader] deployPluginFromUnit Unable to deploy plugin 'null', file Unit: /Users/ssaasen/dev/atlassian/data/confluence/git/master/bundled-plugins/classes (1294296596000)
java.lang.IllegalArgumentException: The artifact URI file:/Users/ssaasen/dev/atlassian/data/confluence/git/master/bundled-plugins/classes/ is not a valid plugin artifact
	at com.atlassian.plugin.DefaultPluginArtifactFactory.create(DefaultPluginArtifactFactory.java:38)
	at com.atlassian.plugin.loaders.ScanningPluginLoader.deployPluginFromUnit(ScanningPluginLoader.java:112)
	at com.atlassian.plugin.loaders.ScanningPluginLoader.loadAllPlugins(ScanningPluginLoader.java:89)
	at com.atlassian.plugin.manager.DefaultPluginManager.init(DefaultPluginManager.java:150)
	at com.atlassian.confluence.plugin.ConfluencePluginManager.init(ConfluencePluginManager.java:192)
	at com.atlassian.confluence.plugin.ConfluencePluginManager.processConfluenceReadyEvent(ConfluencePluginManager.java:305)
	at com.atlassian.confluence.plugin.ConfluencePluginManager.onApplicationEvent(ConfluencePluginManager.java:208)
	at org.springframework.context.event.SimpleApplicationEventMulticaster$1.run(SimpleApplicationEventMulticaster.java:77)
	at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:49)