Dear Peterbindi,
It's interesting that reference to the planets should be made in the Murli with no explanation of the meaning. I have heard Dadi Janki refer to planetary influences also. As DJ has (official line) only studied Gyan as we know it there may have been some teaching about the planets and their influences in the Yagya at some stage. Alternatively, it may be that knowledge of the planets in so deeply ingrained in Hindu myth and culture that Bap Dada assumed that anyone approaching Gyan (in India) already has an understanding of this topic. If this is correct double foreigners can consult any single foreigner for clarification.
My main reference here is a book called The Greatness of Saturn by Dr.Robert E.Svoboda. What I write here is either an extract or a paraphrase.
Jupiter is expert in all forms of knowledge. He possesses all virtues and is modest forgiving and happy. His mind and senses are disciplined and his intellect subtle.
From this one may assume that the influences of Jupiter are favourable.
A few notes from other sources :-
Jupiter is associated with Thursday and with Siva.
Siva is an accelerated energy of infinite intelligence and infinite compassion, the source of the highest spiritual teachings. Siva can destroy ego, karma and Maya. He is also the Lord of Time.
Jupiter can give the blessing of receiving and absorbing spiritual teachings and for being genuinely grateful for those teachings and blessings.
From this one may assume that both Jupiter and his associations are favourable.