I am new to LSPDFR, but after my install, i would launch game from r* launcher, and then start Rage. Once rage would try to hook, GTAV would crash and cause the same error this guy is getting. slow system or insufficient permissions. I managed to get this to run by going to my folder. C:\Program Files\Rockstar Games\Grand Theft Auto V.
Right click it and goto security tab , to change permissions click edit. scroll down and select: Users (%Comp. Name%\Users)
Check the box that says full control. Apply, OK. I also did the same for application packages.
This allowed rage to hook for me.