To ensure that the motion sensor works, try setting it so that it controls a lamp module (LM465 or equiv) at the same house/unit setting that you want to control the light switch with. The sensor can be placed anywhere for this test, but if you have the sensor set to work only at night, you may have test it out in a darkened room. You might also have to first turn the lamp on and then off with the controller before the sensor will take over control.
If this test works, then the only other reason that the sensor may not be working with the light switch is the proximity of the sensor to the controller. Also, check the batteries in the sensor. Low batteries will not give as strong a signal as new batteries will.