I just bought the game as well and have been experiencing the exact same problem, among others.
At first, I could actually launch the game but a mandatory patch update is required. The game would automatically download the patch but as it starts to install I get an error that says something like "patch install error message 114 filename (null)." Just running the patch executable also turned up a similar error message.
As of now, I can't even get the game to launch. I keep getting the exact same error you do.
I submitted a request for help with Rockstar's tech support 3 days ago and have yet to hear anything back. Needless to say, after spending $50 on the game I'm getting pretty frustrated that I can't even play it.
If you hear of a fix for this please post it on here or e-mail me. I'll do the same.
*** Good news! I actually got the game to work. I never did hear back from Rockstar but after some troubleshooting of my own the game is up and running. Here's exactly what I did.
-Uninstall the game (I left the Rockstar Social Club Program installed)
-Turned off my antivirus software (I'm using Kaspersky)
-Reinstalled the game (when asked where I wanted to install the game, I used "C:\LANoire")
-After installation, I opened up the "C:\LANoire" folder and clicked on the "LANoire Launcher"
-Allow the game to launch, it will download & install a mandatory patch. After installation, the game will require a restart. It might take a minute for the game to restart, just let it load. Don't try to manually restart the game.
-At this point, the game should finally load up all the way to the main menu.
-Exit the game, I turned my virus protection back on and tried starting the game again via the launcher. It worked!
Good luck, I hope this helps. I haven't started playing the game yet but I'm looking forward to it.