Same Problem here. I saved the Registry-Part with my main oa-key. I create a second Steam-Account and only buy the standalone addon OA. After i logged in to that new account, it founds the installation from my main account, so i could see my new Serial by rightclick on OA. With the tool "arma2oa_keychanger" i changed the key, and also saved the Reg-Part with it, so i have 2 regfiles with my different keys. But if i change to key Nr. 2, i get some errors because of some DLC-Files ("Failed to load file...\air_pmc.pbo - decryption of headers failed" and so on, like in the first posting). I tried everthing i could in the last hours, deleting the DLC-Part from the regfile, left everything how it was and only change the key and so on, but with Key Nr.2 i always get these damit errors. How is see, ppl who tried it with a second CO and also second DLCs also get the Problem, i think the reason i only buy the OA-Addon is not the Problem. It was great if i can get this working without a complete reinstall and without having a second installation on my harddisk. My main-install works fine, only with the second key - who always brings the DLC-Errors - it will not work. btw: Sry for my bad english. ^^ Greets from germany. PS: In my main Steam-Account i have ARMA II + OA + BAF + PMC, on the second Steam-Account i only have OA. All i want is playing with my main account with 2 different DayZ-Chars, if possible changing only by click on the different Reg-Files.
