I sympathize with the problems you encounter. It is very frustrating to have an instable system, but IMO this is largely due to the fact that you still have the DVStorm installed in your system. Even with PP1.5 there were numerous bugs, shortcomings and failures that were never properly adressed by Canopus. They have their future on Edius, not on Premiere.
I have used the DVStorm for years and it was, with Premiere 6.0 and 6.5, a great card, apart from the sudden crashes. With the advent of PremPro, it became unuseable and you were better off to tear it out of your system and use it as a dust gathering bin in your garage.
PP 2.0 works quite stable in an OHCI environment. I suggest you completely remove all Canopus drivers and hardware from your system and you will notice a marked improvement in responsiveness and stability.
Harm Millaard