Deployment of Confluence 3.0 WAR fails on JBoss AS 5.1

After assembling the confluence war file following the guide at http://confluence.atlassian.com/display/DOC/Installing+Confluence+EAR-WAR+on+JBoss and placing it in the deploy directory of the JBoss server, the following exception occurs:

10:42:26,176 ERROR [ProfileDeployAction] Failed to add deployment: confluence-3.0.0_01.war
org.jboss.deployers.spi.DeploymentException: Error determining structure: confluence-3.0.0_01.war
at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49)
at org.jboss.web.deployers.WARStructure.determineStructure(WARStructure.java:248)
at org.jboss.deployers.vfs.plugins.structure.StructureDeployerWrapper.determineStructure(StructureDeployerWrapper.java:73)
at org.jboss.deployers.vfs.plugins.structure.VFSStructuralDeployersImpl.doDetermineStructure(VFSStructuralDeployersImpl.java:196)
at org.jboss.deployers.vfs.plugins.structure.VFSStructuralDeployersImpl.determineStructure(VFSStructuralDeployersImpl.java:221)
at org.jboss.deployers.structure.spi.helpers.AbstractStructuralDeployers.determineStructure(AbstractStructuralDeployers.java:77)
at org.jboss.deployers.plugins.main.MainDeployerImpl.determineStructure(MainDeployerImpl.java:1004)
at org.jboss.deployers.plugins.main.MainDeployerImpl.determineDeploymentContext(MainDeployerImpl.java:440)
at org.jboss.deployers.plugins.main.MainDeployerImpl.addDeployment(MainDeployerImpl.java:390)
at org.jboss.deployers.plugins.main.MainDeployerImpl.addDeployment(MainDeployerImpl.java:300)
at org.jboss.system.server.profileservice.repository.MainDeployerAdapter.addDeployment(MainDeployerAdapter.java:86)
at org.jboss.system.server.profileservice.repository.ProfileDeployAction.install(ProfileDeployAction.java:61)
at org.jboss.system.server.profileservice.repository.AbstractProfileAction.install(AbstractProfileAction.java:53)
at org.jboss.system.server.profileservice.repository.AbstractProfileService.install(AbstractProfileService.java:361)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.system.server.profileservice.repository.AbstractProfileService.activateProfile(AbstractProfileService.java:306)
at org.jboss.system.server.profileservice.ProfileServiceBootstrap.start(ProfileServiceBootstrap.java:271)
at org.jboss.bootstrap.AbstractServerImpl.start(AbstractServerImpl.java:461)
at org.jboss.Main.boot(Main.java:221)
at org.jboss.Main$1.run(Main.java:556)
at java.lang.Thread.run(Thread.java:636)
Caused by: java.lang.RuntimeException: Failed to initialize ZipWrapper: /home/jboss/jboss-5.1.0.GA/server/default/tmp/vfs-nested.tmp/e3febbf2_xmlrpc-2.0+xmlrpc61.1+sbfix.jar
at org.jboss.virtual.plugins.context.zip.ZipEntryContext.getZipSource(ZipEntryContext.java:286)
at org.jboss.virtual.plugins.context.zip.ZipEntryContext.ensureEntries(ZipEntryContext.java:626)
at org.jboss.virtual.plugins.context.zip.ZipEntryContext.checkIfModified(ZipEntryContext.java:773)
at org.jboss.virtual.plugins.context.zip.ZipEntryContext.getChild(ZipEntryContext.java:817)
at org.jboss.virtual.plugins.context.zip.ZipEntryHandler.createChildHandler(ZipEntryHandler.java:191)
at org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.structuredFindChild(AbstractVirtualFileHandler.java:684)
at org.jboss.virtual.plugins.context.zip.ZipEntryHandler.getChild(ZipEntryHandler.java:165)
at org.jboss.virtual.plugins.context.DelegatingHandler.getChild(DelegatingHandler.java:107)
at org.jboss.virtual.plugins.context.AbstractVirtualFileHandler.structuredFindChild(AbstractVirtualFileHandler.java:689)
at org.jboss.virtual.plugins.context.zip.ZipEntryHandler.getChild(ZipEntryHandler.java:165)
at org.jboss.virtual.plugins.context.DelegatingHandler.getChild(DelegatingHandler.java:107)
at org.jboss.virtual.VirtualFile.getChild(VirtualFile.java:481)
at org.jboss.deployers.vfs.spi.structure.helpers.AbstractStructureDeployer.applyMetadataPaths(AbstractStructureDeployer.java:481)
at org.jboss.deployers.vfs.spi.structure.helpers.AbstractStructureDeployer.createContext(AbstractStructureDeployer.java:455)
at org.jboss.web.deployers.WARStructure.determineStructure(WARStructure.java:204)
... 25 more
Caused by: java.io.FileNotFoundException: /home/jboss/jboss-5.1.0.GA/server/default/tmp/vfs-nested.tmp (Is a directory)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:137)
at org.jboss.virtual.plugins.context.zip.ZipEntryContext.createZipSource(ZipEntryContext.java:361)
at org.jboss.virtual.plugins.context.zip.ZipEntryContext.getZipSource(ZipEntryContext.java:282)
... 39 more