I've never heard of such a thing as overgreasing??? Excess grease finds its way out, doesn't it? And how on earth could it screw up the pawls? :shrug:
My guess is that you've threaded the freewheel on slanted. Get it off, clean and inspect the threads. If all looks ok, regrease and spin it back on, making sure it's straight. It should go all the way easily by hand. It could also be that there is a minor imperfection in the threading that you just have to overcome by force.