Hi hkg, might be obvious, but did you try switching the 3D mode to side-by-side on projector?
Also, are you sure the glasses are "talking" with the projector? The only simple test I can think of is to adjust the 3D brightness (essentially it adjusts the glasses). You will notice your glasses getting brighter or dimmer.
And of course to eliminate any other source, you will want to go straight from your Cable (service) to projector, just in case the receiver really is blocking something.