I got a fixed hub, but as i pedal back wards, to skid/slow down, the cog disengages! It spins off!!!!!!

Im thinking its because i greased the threads, but i dont think that should effect it... i have a spacer there just to make sure the lock ring is making contact... did i go seriosly wrong?!

I have taken the wheel of the bike like 15 times adjusting everything... and it wont work.

I tried tightening the cog using my own pedaling powah and the rotafix method. both have failed.

I hope the hub isn't stripped!

Of course, pics.