It might very well be that the underlying cause is a bug in Maven. I didn't know that it was a known issue so I figured I'd open a JIRA for it. At the very least it documents the problem in case others also stumble upon it.
I think the cause is our use of Ant 1.7 for this plugin. Unfortunately I couldn't find a corresponding Maven JIRA for it, even though I vaguely recall having seen one before. The upgraded Ant version can explain the lack of response on the Maven lists, as the current Maven plugins are all still using Ant 1.6.
> Unable to use commons:jira-page on Windows
> ------------------------------------------
>
> Key: COMMONSSITE-35
> URL:
https://issues.apache.org/jira/browse/COMMONSSITE-35> Project: Commons All
> Issue Type: Bug
> Components: Commons Build Plugin
> Reporter: Dennis Lundberg
>
> I am unable to use the commons:jira-page goal on Windows. It seems to be a problem with spaces in the path.
> Here is the stack trace I get:
> {noformat}
> G:\apache\commons\trunks-proper\exec>mvn commons:jira-page
> [INFO] Scanning for projects...
> [INFO] Searching repository for plugin with prefix: 'commons'.
> [INFO] ------------------------------------------------------------------------
> [INFO] Building Commons Exec
> [INFO] task-segment: [commons:jira-page]
> [INFO] ------------------------------------------------------------------------
> [INFO] [commons:jira-page]
> [INFO] ------------------------------------------------------------------------
> [ERROR] FATAL ERROR
> [INFO] ------------------------------------------------------------------------
> [INFO] null
> Illegal character in path at index 18: file:/C:/Documents and Settings/dlg01/.m2/repository/org/apache/ant/ant/1.7.0/ant-1.7.0.jar
> [INFO] ------------------------------------------------------------------------
> [INFO] Trace
> java.lang.IllegalArgumentException
> at java.net.URI.create(URI.java:838)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:324)
> at org.apache.tools.ant.launch.Locator.fromURI(Locator.java:162)
> at org.apache.tools.ant.launch.Locator.getResourceSource(Locator.java:119)
> at org.apache.tools.ant.launch.Locator.getClassSource(Locator.java:90)
> at org.apache.tools.ant.Project.setAntLib(Project.java:313)
> at org.apache.tools.ant.Project.initProperties(Project.java:309)
> at org.apache.tools.ant.Project.init(Project.java:295)
> at org.codehaus.plexus.component.factory.ant.AntScriptInvoker.initializeProject(AntScriptInvoker.java:251)
> at org.codehaus.plexus.component.factory.ant.AntScriptInvoker.invoke(AntScriptInvoker.java:174)
> at org.apache.maven.script.ant.AntMojoWrapper.execute(AntMojoWrapper.java:52)
> at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:447)
> at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:539)
> at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:493)
> at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:463)
> at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:311)
> at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:278)
> at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:143)
> at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:333)
> at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:126)
> at org.apache.maven.cli.MavenCli.main(MavenCli.java:282)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:324)
> at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
> at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
> at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
> at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
> Caused by: java.net.URISyntaxException: Illegal character in path at index 18: file:/C:/Documents and Settings/dlg01/.m2/repository/org/apache/ant/ant/1.7.0/ant-1.7.0.jar
> at java.net.URI$Parser.fail(URI.java:2752)
> at java.net.URI$Parser.checkChars(URI.java:2925)
> at java.net.URI$Parser.parseHierarchical(URI.java:3009)
> at java.net.URI$Parser.parse(URI.java:2957)
> at java.net.URI.<init>(URI.java:574)
> at java.net.URI.create(URI.java:836)
> ... 31 more
> [INFO] ------------------------------------------------------------------------
> [INFO] Total time: 2 seconds
> [INFO] Finished at: Sat Jun 28 07:58:01 CEST 2008
> [INFO] Final Memory: 6M/11M
> [INFO] ------------------------------------------------------------------------
> {noformat}