Sometimes the jobscheduler_event.cmd script raises "The process cannot access the file ..."

Current Situation
Sometimes the script jobscheduler_event.cmd raises "The process cannot access the file because it is being used by another process."
This is a resumption of JITL-101. The procedure to get temporary filenames are improved but it seems that is still not safe enough.

Desired Behavior
The error "The process cannot access the file because it is being used by another process." should be avoided.