Running a jumper ground wire from panel to non grounded outlet
What you have done was recently made legal under NEC 2014.

The only hitch is that a 20A circuit requires 12 AWG ground wire.  So if the circuits were 20A, they are now 15A.    

A ground is nothing but a safety shield.  No appliance should be flowing current to ground, not even the GFCI.   

You may have already had a ground fault

If a device flows current to ground and the ground is not hooked up, it will "float" the ground to a potentially hazardous voltage, energizing whatever part of your grounding system does exist, e.g. Chassis of equipment, coverplate screws on outlets, etc.    However no current will flow unless there's a path back to source.   

Suppose you already a GFCI in such a situation?  Since no current is flowing, it would not trip a GFCI.  This is safe because if you did get shocked, then current would be flowing and the GFCI would trip.  

By adding the ground, you created the path back to source, which is assuring that the GFCI trips. 

This is laying bare the fact that you have an appliance with a ground fault.  You did before, just your lack of ground was concealing it.  

Since this is a hot-ground or neutral-ground fault, it is unlikely to be the wiring, which has never been near a ground.  I would look hard at appliances.