I had to do a reg edit to get this to work, my versions the Sprocket combined operations download but it wasn't combining when installing Arma2OA. Had to change a line in my reg (windows 7 64)
YOU CAN DESTROY YOUR WINDOWS INSTALLATION EDITING YOUR REGERSTRY IF YOUR NOT COMFITABLE WITH THAT POSSIBILITY DON'T TRY THIS, I TAKE NO RESPONSIBILITY FOR ANY DAMAGE YOU DO!
ok open regedit and find your arma2 key (mine was [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Bohemia Interactive Studio\ArmA 2]) Export it to a .reg file
Open the .reg file and add this line with your arma 2 install directly in it (if different) something like this:
"MAIN"="C:\\Program Files (x86)\\Bohemia Interactive\\ArmA 2"
So Before:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Bohemia Interactive Studio\ArmA 2]
"KEY"=hex:xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx
and After:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Bohemia Interactive Studio\ArmA 2]
"MAIN"="C:\\Program Files (x86)\\Bohemia Interactive\\ArmA 2"
"KEY"=hex:xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx
Save it and double click on the file to add it to the registry
Install Arma2OA and it should select your arma 2 install directory automatically if its going to work,
Worked a treat for me, obviously if the install directory line is already in the arma 2 reg this isn't your problem :)