This passage from "Shree Skanda-Purana" is quite dubious for me - can't understand either the Mantra of ArunaShankara must be uttered or simply The Name.
Still not crucial for me at all - as I am 100000000000000000% happy with my Shree Shree MahaLakshmi-Narayana Devotion.
Against bad dreams and all the other negative flurries we recite "Shree MahaLakshmi-Kavacha" and for other cases (sneeze, falter, danger) Shree AshtaAkshara Mantra of Bhagavan Shree Narayana must be recited (I presume, just my guess) as I am very doubtful about the theory that any danger or bad dream can adverse bhakti-yogini protected by "Shree MahaLakshmi-Kavacha".