Islamic Interpretation of Dreams (Ibn-i Sirin):
(Betting; Casting lots; Games; Risk) Gambling in a dream denotes something groundless, distress, falsehood or an unattainable goal.
If one bets money or something with an adversary and wins his bet in a dream, it means that he will overcome him. Generally speaking, betting or gambling in a dream means quarrels, disputes, uptightness or agony in wakefulness.
(Also see Casting lots; Distress; Games; Uptight; Worries)