@TheCoco17,

The ground should be present in all wall boxes and is a requirement for the proper function of the device, let alone helps in preventing the device from becoming overloaded.

You are correct, though; there are lights or fixtures that will not accept a dimming signal; you are looking for bulbs or fixtures indicating that they are Leading Edge Dimming / Triac Phase Cut compatible.

Lastly, it is important to remember that there are a variety of wiring setups out there. It is possible that you do not have a compatible wiring configuration, such as if the light is actually between the switch and breaker, rather than after the switch.