Trying to wire a gfi receptical with 14/2 w/gnd for a garbage disposal, in a very old house and the supply wire is not grounded, as far as I understand in electricity, you can't have a ground fault interuption without being grounded, also I tried and the receptical didn't work- it's got to be that, how do I ground this one circuit without rewiring the kitchen or messing with the breaker box, thanks in advance

GFCI's will work without grounds. Outlets using them in this fashion must be labeled as such. e.g. "No Ground". They detect the difference in current flow in the hot and neutral leg.

They can also check for a "shared neutral" or a "grounded neutral".

The garbage disposal doesn't need a ground to operate.

Why are you installing a GFCI? For the 3 prong receptacle?

Although the disposal doesn't need a ground to operate, It does need a ground, so if hot breaks free inside disposal and touchs case, the breaker will trip. With no ground, the GFI would protect this.
If it is 14-2, it should have a black, white, and Ground. Is this ground not intact, Or do you think 14-2 means only 2 conductors and no ground?