The game always starts up and lcpdfr loads fine but it randomly crashes while im in game. The last crash happened while in pursuit of a vehicle.

Do you have a legal copy of GTA IV? 

Yes, bought it on steam

Are you running the game as administrator? 

Ran it as admin and played for a while but then crashed due to a "fatal error". Attatched new logs from last crash.

Are you running both exe's as administrator? 

Yes, still crashing.

How often do these crashes occur? 

It varies. Sometimes I can play the game for an hour or two with no problems but just today I only played for about 10 min and it crashed. I can remember two times it happened when i pointed my gun at a person in a car.

Sounds like a pretty standard error, and a pretty decent gameplay time. It is however known that the game will crash when aiming at a person in a vehicle and pressing 'e'. I'm sure the devs are working on it.