Source: The Great Interpretation of Dreams (Ibn Sirin)
Walking backwards in a dream indicates retreating from a matter, corruption in religion, and change of condition for the worse.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Walking backwards indicates regret over a past matter or abandoning work.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Walking backwards is interpreted as worry and change of condition for the worse.