To properly engineer an Affliction Warlock script, you need to be able to query the number of instances of Unstable Affliction that are running on the target. Unfortunately, the mechanism in the current script (target.DebuffStacks) won't work because WoW doesn't consider multiple applications of UA to be multiple stacks of the same debuff. Instead, each debuff (up to 5) is assigned its own spell ID. I have written a poor-man's "UnstableStacks()" function that counts up the number of of these (the spell IDs are in a consistent range) and returns the count, but this strikes me as the sort of thing for which there probably ought to be a built-in function.

At any rate, the existing script references a function that simply doesn't work.