Rad74ss and Luckyshadow gave you some good advice. Especially about bashing your lead man. Many electricians and technicians, who should know better, do not know how to handle a drain wire. Improper handling of a drain wire can cause much grief, and the grief is amplified by the size of your system.
I would like to expand a little about using shielded wire (usually two conductor shielded cable, 12 to 22 gage) as is found in audio, control and in instrumentation systems (you will encounter it everywhere) :
1-the silver (bare) wire is known as a drain wire, not a ground wire. The drain wire is usually connected at the panel end, and is usually not connected at the far end of its' run.
2-a two conductor shielded cable in a system may pass through several splice points in running from end to end. At any splice point in the run, the silver (bare) wire must be treated as an ungrounded conductor. Always think of that bare drain wire as a conductor that the factory forgot to insulate. You must do the insulation for the factory at every point in the run where the conductors are spliced or terminated.
3-never allow the silver (bare) drain wire (or the foil) to contact anything throughtout the run, end to end.
4-never bunch (connect more than two) drain wires at any point in the system, including at the panel end. You may encounter a cable with many two conductor (with drain) cables contained under one common jacket. Each will still be built the same as one two conductor cable, and each drain wire must be insulated individually.
Remember: "we don't need no stinkin' ground loops"