GFCI wont work correctly
Do not alter wiring of energized circuits.  ALWAYS turn off the power.

I've never heard of any GFCI that cares about about ground. The point of a GFCI is they can provide protection even when a ground is not provided.

GFCIs have an "in" and an "out".  You must not reverse these.  The "in" is labeled LINE and the "out" is labeled LOAD.  Make sure you're wiring the power from the panel into the LINE terminals.