Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Falling from a high place indicates despair of a hoped-for matter, or a change of situation from good to bad. If he falls onto a good place like a mosque or a garden, his change will be for the better.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Falling indicates falling into sin or strife. Surviving it is salvation from that. Falling from an animal indicates a difficult journey or loss of strength.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Falling is interpreted as a change of situation. If no harm befalls him, the change is for the better. If he suffers a fracture or wound, the change is for the worse and a calamity.