I now get this “Error” message, and I also get the script screen, but no MultiSav action any more.
I am using LO version 6.04.02, with Ubuntu 16.04.4 LTS
It is MultiFormatSave (not MultiSave) Sorry about providing the incorrect extension name.
(Edited by @Lupp to get the additional info given by the OriginalQuestioner to the correct place.
After this edit Lupp deleted the answer that was none.)