Ok...the first Setup is not executed anymore...that's the Problem. Which is strange..cause it depends on nothing else than a yes/no Inputdialog

Is the part inside the if statement being executed? You can add an /echo inside it to see if it is.

The easiest way to debug a script, to track down the cause of an issue, is to add /echo commands to your script in several locations. This will allow you to see which parts of the script are executing and the contents of specific %variables at that point. This should help you narrow down the cause of the issue you are seeing.