WHISKEYOSCARMIKE

When I try to connect to any ARMA II: OA servers I receive the error "You cannot play/edit this mission it is dependant on downloadable content that has been deleted. Chernarus, caweapons_ammoboxes, CAWater, cawater2_fishing-boat. Does anyone know where I can find these missing files?? I have tried redownloading OA from Steam and verifying the files but I am still getting this error. Can anyone help please??