I also have the exact same problem only since I tried to re-install. After having my hard drives replaced I decided to download a fresh copy instead of moving over files, everything seemed to be fine I had checked a wasteland server after i finished installing both Arma 2 and OA, all worked fine but after I installed Dayz Mod and tried to join I get the same problem either stuck at wait for host, stuck at receiving mission file or just freezes once I hit OK or disconnect, this is for both Dayz and arma servers. Tried moving over the old files and replacing new does not work and steam keeps download a non validated file which seems to never be fixed.
