The following META-INF/application.xml results in a stacktrace during deployment (see below):
<?xml version="1.0" encoding="UTF-8"?>
<application xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/application_6.xsd"
version="6">
<display-name>Beispiel 2</display-name>
<module>
<ejb>hskaEJB.jar</ejb>
</module>
<module>
<web>
<web-uri>hskaWeb.war</web-uri>
<context-root>/hska</context-root>
</web>
</module>
<module>
<ejb>testHskaEJB.jar</ejb>
</module>
<module>
<java>testHskaClient.jar</java>
</module>
</application>

Stacktrace:
13:50:39,195 ERROR [org.jboss.kernel.plugins.dependency.AbstractKernelController] Error installing to Parse: name=vfsfile:/C:/Users/Public/Documents/eclipse-workspace-swe2/.metadata/.plugins/org.jboss.ide.eclipse.as.core/JBoss_6.0_Runtime_Server1266414248806/deploy/hska.ear/ state=PreParse mode=Manual requiredState=Parse: org.jboss.deployers.spi.DeploymentException: Error creating managed object for vfsfile:/C:/Users/Public/Documents/eclipse-workspace-swe2/.metadata/.plugins/org.jboss.ide.eclipse.as.core/JBoss_6.0_Runtime_Server1266414248806/deploy/hska.ear/
at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49)
at org.jboss.deployers.spi.deployer.helpers.AbstractParsingDeployerWithOutput.createMetaData(AbstractParsingDeployerWithOutput.java:362)
at org.jboss.deployers.spi.deployer.helpers.AbstractParsingDeployerWithOutput.createMetaData(AbstractParsingDeployerWithOutput.java:322)
at org.jboss.deployers.spi.deployer.helpers.AbstractParsingDeployerWithOutput.createMetaData(AbstractParsingDeployerWithOutput.java:294)
at org.jboss.deployers.spi.deployer.helpers.AbstractParsingDeployerWithOutput.deploy(AbstractParsingDeployerWithOutput.java:234)
at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:179)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1660)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1378)
at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1319)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:378)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:2029)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:1050)
at org.jboss.dependency.plugins.AbstractController.executeOrIncrementStateDirectly(AbstractController.java:1289)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1213)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1107)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:918)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:633)
at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:898)
at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:677)
at org.jboss.system.server.profileservice.repository.MainDeployerAdapter.process(MainDeployerAdapter.java:117)
at org.jboss.system.server.profileservice.hotdeploy.HDScanner.scan(HDScanner.java:409)
at org.jboss.system.server.profileservice.hotdeploy.HDScanner.run(HDScanner.java:294)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:181)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:205)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.Exception: The xml hska.ear/META-INF/application.xml is not well formed!
at org.jboss.xb.util.JBossXBHelper.parse(JBossXBHelper.java:231)
at org.jboss.xb.util.JBossXBHelper.parse(JBossXBHelper.java:206)
at org.jboss.deployers.vfs.spi.deployer.SchemaResolverDeployer.parse(SchemaResolverDeployer.java:137)
at org.jboss.deployers.vfs.spi.deployer.SchemaResolverDeployer.parse(SchemaResolverDeployer.java:121)
at org.jboss.deployment.AppParsingDeployer.parse(AppParsingDeployer.java:79)
at org.jboss.deployment.AppParsingDeployer.parse(AppParsingDeployer.java:46)
at org.jboss.deployers.vfs.spi.deployer.AbstractVFSParsingDeployer.parseAndInit(AbstractVFSParsingDeployer.java:315)
at org.jboss.deployers.vfs.spi.deployer.AbstractVFSParsingDeployer.parseAndInit(AbstractVFSParsingDeployer.java:297)
at org.jboss.deployers.vfs.spi.deployer.AbstractVFSParsingDeployer.parse(AbstractVFSParsingDeployer.java:221)
at org.jboss.deployers.spi.deployer.helpers.AbstractParsingDeployerWithOutput.createMetaData(AbstractParsingDeployerWithOutput.java:348)
... 29 more