I would address the fixtures as follows:
Fixture 1 - ALL switches OFF (DMX Start Channel 1)
Fixture 2 - Switches 2 and 3 ON (DMX Start Channel 7)
Fixture 3 - Switches 3 and 4 ON (DMX Start Channel 13)
Fixture 4 - Switches 2 and 5 ON (DMX Start Channel 19)
The start channel is the first channel number that a certain fixture will respond to. Since the Mighty Scan utilizes 6 channels, fixture 1 uses channels 1-6, fixture 2 uses channels 7-12, fixture 3 uses channels 13-18, and fixture 4 uses channels 19-24.
I'm not personally familiar with the Operator, but I would assume it will talk to the fixtures addressed this way (at least it should). These addresses are the exact ones I use for my Mightys in conjunction with the Show Designer, but they will work with any DMX controller, so the Operator should be no exception.
If a fixture still seems to act funny, make sure the cable run is terminated and all cables are in good shape. Try to isolate the fixture one-on-one with the controller to narrow things down.
I just had to replace all of my XLR cables with higher grade ones because I was experiencing AC-power induced signal interference. Although the cables metered out OK, there was still a problem with the shielding somewhere.
Best,
-Tech