This redownloaded those files and the game started up fine. rpf-files, and then using the 'verify the integrity of the game cache' option in steam. My fix was to delete all the files except the big. My mistake was made when I tried to save some time downloading by transferring some files from a friend of mine, and by doing so I most likely got some files from his social club folder that caused the problem.
As I understand it it is a problem with linked accounts and social club.
I had the same problem and did some research.
