restoreDT returns with an error from the "tar -xhv -f" command

When migrating from Blueworx Voice Response Version 4.2 to Blueworx Voice Response Version 6.1 the restoreDT command can fail with the following error message:
DATA UPGRADE FAILED: Error During tar -xhv -f .admclass_table admclass_table rd.data…
   (more archive files) 
This failure occurs even though the system has enough free space and all file permissions are set correctly.

The reason for the failure is that the wrong version of saveDT from Blueworx Voice Response Version 4.2 was used to create the application and configuration backup.

Use the version of saveDT dated August 2009 which includes all updates for migration to Blueworx Voice Response Version 6.1 to create the migration archive and then run restoreDT again. To obtain the latest version of saveDT before migrating to Blueworx Voice Response Version 6.1, please update Blueworx Voice Response Version 6.1 to at least fix level 4.2.0.499 and use the installed version of the saveDT script.