First, recheck your wiring. Sometimes people connect rears up to "B" speaker terminals.
Second, check your speaker assignments. Read your manual for this.
Most receivers send sequential tones to the individual speakers for balancing. Find this option and try that.
Do you have an "All channel stereo"* mode? If so, this should send something to all your channels. Try that.
Movies generally don't have much action in the surround channels and are usually pretty silent aside from an occasional gunshot or some ambiance cues. Could this be the case?
* Or something like that...