Scheduler error in logs after running for some time

2010-12-24 08:31:06,197 [DefaultQuartzScheduler_Worker-3] ERROR xwiki.XWiki                     - Failed to extract #includeMacros targets from provided content [$msg.get("watchlist.job.hourly")] 
java.lang.ArrayIndexOutOfBoundsException: 31
        at org.apache.oro.text.regex.Perl5Matcher.__findFirst(Unknown Source)
        at org.apache.oro.text.regex.Perl5Matcher.__interpret(Unknown Source)
        at org.apache.oro.text.regex.Perl5Matcher.contains(Unknown Source)
        at com.xpn.xwiki.util.Util.getAllMatches(Util.java:133)
        at com.xpn.xwiki.util.Util.getUniqueMatches(Util.java:146)
        at com.xpn.xwiki.XWiki.getIncludedMacros(XWiki.java:6323)
        at com.xpn.xwiki.render.XWikiVelocityRenderer.render(XWikiVelocityRenderer.java:80)
        at com.xpn.xwiki.render.XWikiVelocityRenderer.interpret(XWikiVelocityRenderer.java:55)
        at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:289)
        at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.interpretText(DefaultXWikiRenderingEngine.java:195)
        at com.xpn.xwiki.doc.XWikiDocument.getRenderedTitle(XWikiDocument.java:1285)
        at com.xpn.xwiki.doc.XWikiDocument.getDisplayTitle(XWikiDocument.java:1164)
        at com.xpn.xwiki.plugin.activitystream.impl.ActivityStreamImpl.onEvent(ActivityStreamImpl.java:910)
        at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:278)
        at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:247)
        at org.xwiki.legacy.internal.LegacyEventDispatcher.onEvent(LegacyEventDispatcher.java:97)
        at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:278)
        at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:247)
        at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1479)
        at com.xpn.xwiki.plugin.watchlist.WatchListJob.setPreviousFireTime(WatchListJob.java:170)
        at com.xpn.xwiki.plugin.watchlist.WatchListJob.executeJob(WatchListJob.java:240)
        at com.xpn.xwiki.plugin.scheduler.AbstractJob.execute(AbstractJob.java:75)
        at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:525)