((and EffectInstance) and Flex 2.0.1)
I got this error message when opening up a project developed last year in Flex 2.0 in my new install of Flex Builder 2.0.1 (with Flex SDK 2.0.1).
Simply there's a change in the API that I hadn't noticed. At least not till the time it mattered. Here it is :
import mx.effects.EffectInstance;
....
override protected function initInstance(instance:EffectInstance):void
should be changed to :
import mx.effects.IEffectInstance;
....
override protected function initInstance(instance:IEffectInstance):void
No big drama, although had to think about it for a second and this head's up might help someone else.
Cheers
Matthew