Zenaj: OK, I found out what was wrong.
Microsoft Security Essentials were blocking it, now I added patch to Exclude list, everything worked smoothly.
I have Win 7 SP1 64 bit and I double click on patcher_gog.exe after extracting it, and I get the UAC prompt, enter my admin credentials and the same error message appears as described. I am using Microsoft Security Essentials as well. What exactly do I need to add to what section of exclusions in Micrsoft Security Essentials?
I turned off real time protection and I get the same error.