The ground wire connects to the fixture frame. Might be a green wire to connect it to.
You problem is most probably from the outdoor fixtures. Tell us all the wires in the fixtures. If you only have one cable with one black, white & ground wire, then your problem is not the outdoor fixture.

Thanks for your answer.

The fixtures are double floodlight fixtures. Each has two white wires and two black wires. There is no green wire or screw for grounding to the fixture frame. The supply wire from the house has black, white, and bare.

I wonder if the bare ground wire was left protruding from the fixture when it was screwed down, creating a connection to the frame... That would explain the paint on the wire.

I will try attaching the ground to the fixture frame somehow.

if hooking up the ground fixes it, you have other problems. the ground has no function in a light circuit, or most any other circuit for that matter, other than as a safety.

if you only have 1 cable coming into the fixture from house wiring, then either they pulled a connectioin loose at a junction point, or tripped a protection devie somewhere. did you turn all breakers fully off, then back on? breakers only trip the handle halfway, you have to turn to OFF, then back to on to reset them.

you could also have a bad GFCI soemwhere if none of them show tripped. it is time to start workign the circuit backwards to find the problem.

So, you're saying that the outside lights' ground wires really should have no bearing on the function of the inside or outside lights?

If this is true, then the problem is not related to the lights being disconnected, since I have connected the black wires and white wires (house to fixture) already and this did not fix the problem.

Any other thoughts. It may be time to have the contractor call his electrician.

Double check the breakers as suggested and make sure there is not a hidden GFCI somewhere that has tripped. Also check the connections at the receptacle that is not working and the closest working receptacle that is on the same circuit. It is possible that a push-in type connection on one of these receptacles has come loose.

If you only have one of each colour of wire then the fixture wiring has no baring on the internal devices that are dead. They either tripped a breaker, a GFCI or drove a nail or screw into a cable and damaged it.