Does the error box have text in the title bar? Is there anything in the error box at all?
Does this happen with any emitter you load, or only certain ones?
Do you have any other effects applied, or is pIAE the only one?
Is it applied to footage, a solid, or adjustment layer?
Try a simple comp with a solid and only pIAE applied and see if the same thing happens. If it does, then close AE and check if your graphics card has updated video drivers -- go to your card manufacturer's website, which may be ATI, NVIDIA, or others.