2006 BMW X3 Car not starting

First of all, I strongly recommend against jump starting BMW automobiles, if the battery will not start the car, place a battery charger on it and be patient, jump starts can cause electronic issues with the modules in the car. The battery will most likely require replacement if it is as old as the car, old batteries meaning 4-5 years old and of original equipment. The clicking is from a weak battery, booster cables from the parts house do not have the current carrying capacity to handle starting, as it can take 100+ amperes.