Tasks are run only on one Publisher - Error: ScriptExecuter :failed to calculate load; no script compiled

In QlikView server, Load balancing is configured to run tasks on different publisher when load is high, although in the task logs, only one Publisher is running them.
In the Distribution Service LoadBalancer.log and in the Application Windows events on the Publisher, this error is continuously registered :

       -Error: ScriptExecuter :failed to calculate load, no script compiled


Environments:

    QlikView server (Publisher) > All versions

Check the ProgramData Distribution Service folder for corruption (usually detected when files are not updated):

The path to the QlikView Distribution Service (QDS) application data folder can be found in the QlikView Management Console (QMC) under System --> Setup --> pick the QDS on the left --> General --> Application Data Folder    (default value: C:\ProgramData\QlikTech\DistributionService)

- Stop the QlikView Distribution Service
- Rename it to make a backup
- Start again the QlikView Distribution Service and run a test, check if tasks are correctly load balanced by checking the task logs in the QMC.