NED

Got the same error . Arma2 as DVD Version and OA bought through Spocket. EDIT: I found a solution for me. I installed Arma 2 and AO in 2 different folders and had Arma 2 already patched. So I uninstalled both and deleted all folders that were still left. After that I installed Arma 2 without patching it and then installed AO. After AO installation I installed the AO Patch 1.50 - 1.55 and it also patched Arma 2 to Version 1.08 i think. Now everything works fine. Hope it helps and sorry for my English.