touch of war does not trigger redeployment

I try to deploy a war to a jboss AS6 that runs on a ec2 instance. I therefore scp it directly to the deploy folder.
I then see a deployment exception in the server log, this occurs before the scp is completely finished:

2011-02-10 06:20:33,010 WARN [org.jboss.profileservice.deployment.hotdeploy.HDScanner] (HDScanner) Failed to add deployment: vfs:///opt/jboss-as6/server/default/deploy/gwt-helloworld.war: org.jboss.deployers.spi.DeploymentException: Failed to mount archive: "/opt/jboss-as6/server/default/deploy/gwt-helloworld.war"
at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49) [:2.2.0.GA]
at org.jboss.deployers.vfs.plugins.structure.AbstractVFSArchiveStructureDeployer.mountArchive(AbstractVFSArchiveStructureDeployer.java:132) [:2.2.0.GA]
at org.jboss.deployers.vfs.plugins.structure.AbstractVFSArchiveStructureDeployer.determineStructure(AbstractVFSArchiveStructureDeployer.java:55) [:2.2.0.GA]
at org.jboss.deployers.vfs.plugins.structure.StructureDeployerWrapper.determineStructure(StructureDeployerWrapper.java:73) [:2.2.0.GA]
at org.jboss.deployers.vfs.plugins.structure.VFSStructuralDeployersImpl.doDetermineStructure(VFSStructuralDeployersImpl.java:197) [:2.2.0.GA]
at org.jboss.deployers.vfs.plugins.structure.VFSStructuralDeployersImpl.determineStructure(VFSStructuralDeployersImpl.java:222) [:2.2.0.GA]
at org.jboss.deployers.structure.spi.helpers.AbstractStructuralDeployers.determineStructure(AbstractStructuralDeployers.java:77) [:2.2.0.GA]
at org.jboss.deployers.plugins.main.MainDeployerImpl.determineStructure(MainDeployerImpl.java:1106) [:2.2.0.GA]
at org.jboss.deployers.plugins.main.MainDeployerImpl.determineDeploymentContext(MainDeployerImpl.java:417) [:2.2.0.GA]
at org.jboss.deployers.plugins.main.MainDeployerImpl.addDeployment(MainDeployerImpl.java:367) [:2.2.0.GA]
at org.jboss.deployers.plugins.main.MainDeployerImpl.addDeployment(MainDeployerImpl.java:277) [:2.2.0.GA]
at org.jboss.system.server.profileservice.deployers.MainDeployerPlugin.addDeployment(MainDeployerPlugin.java:77) [:6.0.0.Final]
at org.jboss.profileservice.dependency.ProfileControllerContext$DelegateDeployer.addDeployment(ProfileControllerContext.java:133) [:0.2.2]
at org.jboss.profileservice.deployment.hotdeploy.HDScanner$HDScanAction.deploy(HDScanner.java:221) [:0.2.2]
at org.jboss.profileservice.deployment.hotdeploy.HDScanner$HDScanAction.complete(HDScanner.java:192) [:0.2.2]
at org.jboss.profileservice.management.TwoPCActionWrapper.doComplete(TwoPCActionWrapper.java:57) [:0.2.2]
at org.jboss.profileservice.management.actions.AbstractTwoPhaseModificationAction.complete(AbstractTwoPhaseModificationAction.java:74) [:0.2.2]
at org.jboss.profileservice.management.actions.AbstractTwoPhaseModificationAction.prepare(AbstractTwoPhaseModificationAction.java:95) [:0.2.2]
at org.jboss.profileservice.management.ModificationSession.prepare(ModificationSession.java:87) [:0.2.2]
at org.jboss.profileservice.management.AbstractActionController.internalPerfom(AbstractActionController.java:234) [:0.2.2]
at org.jboss.profileservice.management.AbstractActionController.performWrite(AbstractActionController.java:213) [:0.2.2]
at org.jboss.profileservice.management.AbstractActionController.perform(AbstractActionController.java:150) [:0.2.2]
at org.jboss.profileservice.management.AbstractActionController.perform(AbstractActionController.java:135) [:0.2.2]
at org.jboss.profileservice.deployment.hotdeploy.HDScanner.scan(HDScanner.java:146) [:0.2.2]
at org.jboss.profileservice.deployment.hotdeploy.HDScanner.run(HDScanner.java:90) [:0.2.2]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [:1.6.0_20]
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:351) [:1.6.0_20]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:178) [:1.6.0_20]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:165) [:1.6.0_20]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:267) [:1.6.0_20]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [:1.6.0_20]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [:1.6.0_20]
at java.lang.Thread.run(Thread.java:636) [:1.6.0_20]
Caused by: java.util.zip.ZipException: error in opening zip file
at java.util.zip.ZipFile.open(Native Method) [:1.6.0_20]
at java.util.zip.ZipFile.<init>(ZipFile.java:131) [:1.6.0_20]
at java.util.jar.JarFile.<init>(JarFile.java:150) [:1.6.0_20]
at java.util.jar.JarFile.<init>(JarFile.java:114) [:1.6.0_20]
at org.jboss.vfs.spi.JavaZipFileSystem.<init>(JavaZipFileSystem.java:94) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.spi.JavaZipFileSystem.<init>(JavaZipFileSystem.java:80) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.VFS.mountZip(VFS.java:428) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.VFS.mountZip(VFS.java:454) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.util.automount.Automounter$RegistryEntry.mount(Automounter.java:237) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.util.automount.Automounter$RegistryEntry.access$000(Automounter.java:208) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.util.automount.Automounter.mount(Automounter.java:117) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.vfs.util.automount.Automounter.mount(Automounter.java:77) [jboss-vfs.jar:3.0.0.GA]
at org.jboss.deployers.vfs.plugins.structure.AbstractVFSArchiveStructureDeployer.performMount(AbstractVFSArchiveStructureDeployer.java:145) [:2.2.0.GA]
at org.jboss.deployers.vfs.plugins.structure.AbstractVFSArchiveStructureDeployer.mountArchive(AbstractVFSArchiveStructureDeployer.java:128) [:2.2.0.GA]
... 31 more

As soon as my scp transfer is finished, I get back to the admin-console and wait to see if my war was picked as web application. It is not. I don't see any further scanner activity in the server log.
I then touch the war and check the web-apps in the admin-console again. No reaction. There is no scanner activity in the server log.