Hi,
We stopped testing on the Flash platform since Unity announced it was dropping support for it. I can't see it in the list of platforms in 4.3.1 which makes this impossible to work out either. How do you get that to show up in the list of platforms?
You will probably need to #if !UNITY_FLASH out a bunch more code - the flash exporter, as you probably know, was never completed properly and doesn't support many many things in Unity.