Virtual File System Errors - java.util.ConcurrentModificationException at java.util.AbstractList$Itr.checkForComodification

This is on a CF9 server on Windows 2008

We do a lot of writing to and then including from, the VFS (Virtual File System). Very intermittently, we get these errors when attempting to write to the RAM disk. Retrying the failed WRITE operation usually succeeds.

The filename is always a unique file name created with createUUID() in the filename.

I have read that this stack trace error is related to deleting items from an array while accessing it at the same time. Do I need to lock all access to the VFS? I feel like that would really hurt performance.  Should I clean up the temporary files created and written to the VFS at the end of the request, or maybe I should schedule it to run daily so there is less contention for those resources?

java.util.ConcurrentModificationException at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372) at java.util.AbstractList$Itr.next(AbstractList.java:343) at org.apache.commons.vfs.provider.ram.RamFileSystem.listChildren(RamFileSystem.java:100) at org.apache.commons.vfs.provider.ram.RamFileObject.doListChildren(RamFileObject.java:81) at org.apache.commons.vfs.provider.AbstractFileObject.getChildren(AbstractFileObject.java:557) at coldfusion.vfs.VFile.listFiles(VFile.java:480) at coldfusion.tagext.io.FileUtils.recursiveDirectorySize(FileUtils.java:122) at coldfusion.tagext.io.FileUtils.getDirectorySize(FileUtils.java:112) at coldfusion.runtime.CFPage.GetVFSMetaData(CFPage.java:634) at cfmonitor2ecfm1275412139.runPage(C:\inetpub\wwwroot\LF\web\health\monitor.cfm:44) at coldfusion.runtime.CfJspPage.invoke(CfJspPage.java:231) at coldfusion.tagext.lang.IncludeTag.doStartTag(IncludeTag.java:416) at coldfusion.filter.CfincludeFilter.invoke(CfincludeFilter.java:65) at coldfusion.filter.ApplicationFilter.invoke(ApplicationFilter.java:360) at coldfusion.filter.RequestMonitorFilter.invoke(RequestMonitorFilter.java:48) at coldfusion.filter.MonitoringFilter.invoke(MonitoringFilter.java:40) at coldfusion.filter.PathFilter.invoke(PathFilter.java:94) at coldfusion.filter.ExceptionFilter.invoke(ExceptionFilter.java:70) at coldfusion.filter.ClientScopePersistenceFilter.invoke(ClientScopePersistenceFilter.java:28) at coldfusion.filter.BrowserFilter.invoke(BrowserFilter.java:38) at coldfusion.filter.NoCacheFilter.invoke(NoCacheFilter.java:46) at coldfusion.filter.GlobalsFilter.invoke(GlobalsFilter.java:38) at coldfusion.filter.DatasourceFilter.invoke(DatasourceFilter.java:22) at coldfusion.filter.CachingFilter.invoke(CachingFilter.java:62) at coldfusion.CfmServlet.service(CfmServlet.java:200) at coldfusion.bootstrap.BootstrapServlet.service(BootstrapServlet.java:89) at jrun.servlet.FilterChain.doFilter(FilterChain.java:86) at com.intergral.fusionreactor.filter.FusionReactorCoreFilter.doRequestNoFilter(FusionReactorCoreFilter.java:712) at com.intergral.fusionreactor.filter.FusionReactorCoreFilter.doFusionRequest(FusionReactorCoreFilter.java:341) at com.intergral.fusionreactor.filter.FusionReactorCoreFilter.doFilter(FusionReactorCoreFilter.java:246) at com.intergral.fusionreactor.filter.FusionReactorFilter.doFilter(FusionReactorFilter.java:121) at jrun.servlet.FilterChain.doFilter(FilterChain.java:94) at coldfusion.monitor.event.MonitoringServletFilter.doFilter(MonitoringServletFilter.java:42) at coldfusion.bootstrap.BootstrapFilter.doFilter(BootstrapFilter.java:46) at jrun.servlet.FilterChain.doFilter(FilterChain.java:94) at jrun.servlet.FilterChain.service(FilterChain.java:101) at jrun.servlet.ServletInvoker.invoke(ServletInvoker.java:106) at jrun.servlet.JRunInvokerChain.invokeNext(JRunInvokerChain.java:42) at jrun.servlet.JRunRequestDispatcher.invoke(JRunRequestDispatcher.java:286) at jrun.servlet.ServletEngineService.dispatch(ServletEngineService.java:543) at jrun.servlet.jrpp.JRunProxyService.invokeRunnable(JRunProxyService.java:203) at jrunx.scheduler.ThreadPool$DownstreamMetrics.invokeRunnable(ThreadPool.java:320) at jrunx.scheduler.ThreadPool$ThreadThrottle.invokeRunnable(ThreadPool.java:428) at jrunx.scheduler.ThreadPool$UpstreamMetrics.invokeRunnable(ThreadPool.java:266) at jrunx.scheduler.WorkerThread.run(WorkerThread.java:66)

Any help appreciated,  the VFS is really not working as well as I hoped it would.

Brook