protected override void HookSetDefaultValues(DataRow dataRow)
		{
			if (this.DefaultValues != null)

I don't see where you set this.DefaultValues, so I'm guessing this.DefaultValues == null. Can you set a breakpoint on the if statement and make sure that .DefaultValues isn't an undefined value?

When you say the broken rules are never reported, how are you saving your business object? I mean, what's the line of code that saves it? I don't see anything right away that looks wrong with the rule, if you put a breakpoint in CheckForDuplicateICDACode does it get there?

Mike