Well if he got a jolt when trying to put the bulb in then there must have been power going to it at that stage at least, perhaps that incident caused some damage.
I'd guess that these are screw in (small ES) type bulbs. The live should go to the centre pip, and neutral to the threaded part. You can sometimes touch that threaded part while you screw the bulb in.
No consequence normally (neutral is "safe" to touch) but if neutral is missing, you get current flowing from the centre pip, through the bulb filament and into your hand, as it has nowhere else to go. Doh!
So don't change a bulb with the light switch on, kiddies.
It definitely wouldn't have been able to damage anything though, so I suspect it's just faulty (i.e. the neutral wire isn't connected to the bulb part, inside)
If you feel like buying a multimeter Joans (fiver or so in Maplin) then we can diagnose this properly, or you could return it and try again.