Hi Dario,

The way you are calling the subscript I would start by looking at the following things to rule out the basics:

• You have script.SelectMemory(1, "multicastDefaultFileName") and according to the docs this would try to assign the memory file with the name multicastDefaultFileName to the subscript memory item with id 1
  As far as I am aware in order for this to work you have to have a memory file with this name defined in the memory files section of the automation module (see image below)

• If the above is correct I would check whether your memory file definition in the subscript is using id 1 or to be sure I would try with the overload that accepts a name instead of an id (see docs)