Solution
At times of DIAdem 2015 and DIAdem 2017 (without service pack) we did not ship the VBS engine together with DIAdem, because the engine from the OS was fine. With an update of the OS a new – and unfortunately – not correct working VBS engine was installed and cause the problem.
Please check that your DIAdem 2015/2017 has no file named VBScript.DLL in the DIAdem program folder.
Close DIAdem and copy the VBScript.DLL from any later version like DIAdem 2019 or 2020 (or use the attached file) into the DIAdem 2015/2017 program folder.