Can a homeopathic medicine overdose kill you?

No. Homeopathic medicines are prepared in very dilute quantities, such that above the potencies of 12c or 24x, it's unlikely to find a molecule of the original substance from which the remedy was made. This is what some point to as the "nonsense" of homeopathy -- but dr. Hahnemann wrote of using a spiritual substance to deal with a spiritual, energetic aspect of the person (his or her healing system).
Not likely. Homeopathic medicines are extremely dilute.