Dear Friends,
After I contacted to customer support in BI Studio, Mr Jan Libich offered the folloing solution that worked in my case:
1. Uninstall everything
2. Reboot
3. Install ARMA2
4. Patch ARMA2 to 1.11 version (Two steps: a. patch 1.05, b. patch 1.11)
5. Run ARMA2 Once
6. Install ARMA2 OA
7. Patch ARMA2 OA to 1.60 ver
8. Run ARMA2 OA Once
9. Patch ARMA2 to 1.62 ver
10. Run ARMA2 OA
Now ACR DLC may be added. In my case, I had already BAF and PMC DLCs. I reinstalled them and then I applied again patch 1.60, to pach them to versions
1.03 and 1.02 respectively, and to add the missions of PMC.
Everything worked properly, and I'm now enjoing the new DLC, ACR!
Thumbs up for BI Studio!