1. This is LU, not LU-MP.
2. You need the American 1.0 version of the game if you wish to patch it the normal way. I believe a German patcher is also available from Rockstar Games, so use that if you are able to find it. Otherwise, you may need to find someone willing to give you the American 1.0 executable
legally so you can patch that, or just have them give you an already-patched executable.
3. Make sure you legally own the game and did not pirate it. Piracy is not allowed here, and we can't help you if you pirated your game.