are you thinning your paint? mixing with water instead of applying strait from the paint pot will help a ton. If not that, are you painting in an extreme environment? alot of the time, cold or heat can have unwanted effects on paint.
You might try the Future floor polish thing. I live in the desert and all of my minis were coming out terribly chalky. It is so bad here that I was WATCHING the paint dry, and it was anything but boring. I tried using the floor polish (mixed with water as well) on some small detail pieces and I was very happy with the results. I haven\'t had the chance to try it with larger areas.
I don\'t know how sage this advice is as I am trying this on literally mini #6.