Like Save June 17, This could actually be the problem. What you actual want in electrical terms is for them to run "in parallel" - but they are still in a row. Comments No love lost over fluorescent lights? Include a picture or two with your post, to be on the safe side. The ground wire doesn't actually go through the inner workings of the GFCI, and where the current gets lost to has no bearing on whether the GFCI will trip.
You might consider getting a wiring book or a knowledgeable friend to help on this.
How to Install Fluorescent Lights
I have a question. Pull the switch off the electrical box. This could actually be the problem. If the problem is not in the tube, try changing the starter. What type of ballast Electronic or Magnetic? They don't trip the breaker at that point, but do it when you turn it on a second or occasionally third or forth time.