I must say that the support from BIS regarding this is pretty poor. There was not much response on the foums plus my email never got answered. Another thing is that the patch 1.0 to 1.07 missing the Battleye installer is also lame. There is no mention apart from being buried on these forums about how to overcome it. On the Battleye site you can oly download the .dll files and not the installer. Plus the patch is quite old now and there hasnt been a change to included Battleye.
Anywhooo rant over. I managed to fix the prob by uninstalling Arma2 and OA then reinstalling Arma2...........applying the all version patch and find the Battleye installer. Unfortunatley I had to work this out myself. Perhaps a sticky would ne nice.
BUT thanks to those who posted a reply anyway.
