wiring chandelier problem
a bad ground will not cause a dim burning lamp.
First thing; make sure the lamps are 120 v rated (or there about) lamps. If this came frmo Italy and it has lamps already in it, they are probably not 120 v rated lamps (doesn't cause the problem you are having though)
so, for a lamp to burn partially, you have power leaking to the lamp somehow.
was there already a fixture in this place and it worked fine?
How many wires and what color are they in the box?
BTW: blue wire connects to white in the box. Black to black. Green, green w/ yellow stripe, bare all connect together.
is the switch a switch or is it a dimmer?