When updating files and rebuilding, I keep getting these exceptions:

eclipse.buildId=M20071023-1652
java.version=1.6.0_03
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=linux, ARCH=x86, WS=gtk, NL=en_GB
Command-line arguments: -os linux -ws gtk -arch x86

Error
Thu May 08 18:38:29 CEST 2008
Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".

java.lang.NullPointerException
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveFileSetImpl.matchesPath(ArchiveFileSetImpl.java:123)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveFileSetImpl.matchesPath(ArchiveFileSetImpl.java:119)
at org.jboss.ide.eclipse.archives.core.util.ModelUtil$1.visit(ModelUtil.java:83)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:224)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:229)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:229)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:212)
at org.jboss.ide.eclipse.archives.core.model.ArchivesModel.accept(ArchivesModel.java:136)
at org.jboss.ide.eclipse.archives.core.util.ModelUtil.getMatchingFilesets(ModelUtil.java:91)
at org.jboss.ide.eclipse.archives.core.build.ArchiveBuildDelegate.incrementalBuild(ArchiveBuildDelegate.java:151)
at org.jboss.ide.eclipse.archives.core.build.ArchiveBuildDelegate.projectIncrementalBuild(ArchiveBuildDelegate.java:131)
at org.jboss.ide.eclipse.archives.core.project.ArchivesBuilder.build(ArchivesBuilder.java:78)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:624)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:166)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:197)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:246)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:249)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:214)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:353)
at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:494)
at org.eclipse.core.internal.resources.Project.build(Project.java:75)
at org.eclipse.debug.core.model.LaunchConfigurationDelegate.buildProjects(LaunchConfigurationDelegate.java:397)
at org.eclipse.debug.core.model.LaunchConfigurationDelegate.buildForLaunch(LaunchConfigurationDelegate.java:123)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:727)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:608)
at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:899)
at org.eclipse.debug.internal.ui.DebugUIPlugin$7.run(DebugUIPlugin.java:1102)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

and

Errors running builder 'JBossIDE Packages Builder' on project 'ejb3-beans'.

java.lang.NullPointerException
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveFileSetImpl.matchesPath(ArchiveFileSetImpl.java:123)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveFileSetImpl.matchesPath(ArchiveFileSetImpl.java:119)
at org.jboss.ide.eclipse.archives.core.util.ModelUtil$1.visit(ModelUtil.java:83)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:224)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:229)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:229)
at org.jboss.ide.eclipse.archives.core.model.internal.ArchiveNodeImpl.accept(ArchiveNodeImpl.java:212)
at org.jboss.ide.eclipse.archives.core.model.ArchivesModel.accept(ArchivesModel.java:136)
at org.jboss.ide.eclipse.archives.core.util.ModelUtil.getMatchingFilesets(ModelUtil.java:91)
at org.jboss.ide.eclipse.archives.core.build.ArchiveBuildDelegate.incrementalBuild(ArchiveBuildDelegate.java:151)
at org.jboss.ide.eclipse.archives.core.build.ArchiveBuildDelegate.projectIncrementalBuild(ArchiveBuildDelegate.java:131)
at org.jboss.ide.eclipse.archives.core.project.ArchivesBuilder.build(ArchivesBuilder.java:78)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:624)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:166)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:197)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:246)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:249)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:214)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:353)
at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:494)
at org.eclipse.core.internal.resources.Project.build(Project.java:75)
at org.eclipse.debug.core.model.LaunchConfigurationDelegate.buildProjects(LaunchConfigurationDelegate.java:397)
at org.eclipse.debug.core.model.LaunchConfigurationDelegate.buildForLaunch(LaunchConfigurationDelegate.java:123)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:727)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:608)
at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:899)
at org.eclipse.debug.internal.ui.DebugUIPlugin$7.run(DebugUIPlugin.java:1102)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)