Source:  ZENworks for Servers; Policy and Distribution Services; Policy/Package Agent; Rollback handler

Explanation:  When you install a software package to update existing software, the previous version of the software is stored in a rollback file, in case you want to return to it. This file is stored in the following directory:

ZENWORKS\PDS\TED\SMANAGER\WORKING\ROLLBACK

A rollback file for the software package you are installing already exists.

Possible Cause:  You have installed the identical software package more than once.

Action:  None. You can install the same software package multiple times, but the rollback file is only created during the first installation.