Thanks. I have the Social Club version though. However, from what I understand, the only difference between the Steam and RGSC version is that the Steam version just integrates it with Steam, so I'll give it a shot. I've got the link to the RGSC version too.
EDIT - Yeah, Steam version doesn't work. Going to try the other one now.
EDIT 2 - Other files are working, but still prompts me to update. Guess I have to turn my Internet connection off temporarily when going to play.