Also, could you list the module that is causing the crash?
I had a similar problem to you where the root cause was an improperly formatted AI aircraft texture (different airport, though).
If an AI texture is the problem, the sim should consistently cite "fe.dll" as the problem module.
If that fails, try analyzing your computers memory usage on approach in the default C172 and the CS 757. This can be done in the task manager, just make sure you set it up to show VM usage (View>Select columns and check Virtual Memory size).