Please help an utterly analog person

Duplicati won’t start any more since Version 2.4.0.0 demands a secure secure datafolder. The error message tells me to restrict the permissions of the secure datafolder manually or by using ‘Duplicati.CommandLine.ConfigureTool.exe secure-datafolder’.

The error message does not tell me what to manually restrict the permissions to, and using the above command in a cmd shell returns a “command Duplicati.CommandLine.ConfigureTool.exe not found” (I translate from German).

Obviously I’m missing very basic knowledge at this point. I wouldn’t even know how to search for it. Could anyone point me in the right direction?