Hi, this might be a common issue but I couldn't find a tip, as I backed up my FC2 into a USB from my broken PS3, then copied the files into a new PS3, however a message appeared stating that I am not the authentic gamer or something like that and now all trophies are locked/blocked.

Would appreciate your input.

Hello and welcome to the Forums
I've never heard of this issue. I'm not sure if you can do that. Did you try transferring other games with the USB? I would try posting in the Far Cry Technical Community Help.