Source: The Great Interpretation of Dreams (Ibn Sirin)
Prostration in a dream indicates triumph, victory, long life, and repentance. Prostrating to other than God indicates needs not being met and humiliation.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Prostration indicates humility before God and drawing closer to Him. It indicates Hajj and salvation from dangers.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Prostration is interpreted as triumph and salvation. Whoever sees himself prostrating will get what he wishes.