file delete issues in Windows multi core environment

HI, we are runing PDI 4.2 in a Windows virtual environment (ESX). Everything appears to work fine when the server is configured with a single core, but when we scale up the server to mulitple cores we are running into problems. We have been encountering issues when attempting to delete a file where the system is throwing the following exception:

ERROR 11-10 14:26:26,353 - Is Full Load - org.apache.commons.vfs.FileSystemException: Could notdelete "file:////.../..../...foo.txt".
at org.apache.commons.vfs.provider.AbstractFileObject.deleteSelf(Unknown Source)
at org.apache.commons.vfs.provider.AbstractFileObject.delete(Unknown Source)
at org.apache.commons.vfs.provider.AbstractFileObject.delete(Unknown Source)
at org.pentaho.di.job.entries.deletefiles.JobEntryDeleteFiles.ProcessFile(JobEntryDeleteFiles.java:259)
at org.pentaho.di.job.entries.deletefiles.JobEntryDeleteFiles.execute(JobEntryDeleteFiles.java:211)
at org.pentaho.di.job.Job.execute(Job.java:503)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:642)
at org.pentaho.di.job.Job.execute(Job.java:368)
at org.pentaho.di.job.Job.run(Job.java:288)
Caused by: org.apache.commons.vfs.FileSystemException: Could not delete "file:////.../..../...foo.txt".
at org.apache.commons.vfs.provider.local.LocalFile.doDelete(Unknown Source)
... 16 more

Looking for anyone who has experienced similar issues. The problem exists in multiple PDI jobs. We have looked a the apache doDelete code, and it is not doing anything fancy, so we don't believe this is the root cause. Wondering if there is a compatibility issue with the ESX virtual environment.