Fire crashing

hmm this is the second time I've had trouble rendering a fire particle pass (using sprites). Rendering from the command line would render 2 or 3 frames and then the window would close. Rendering interactively would crash XSI. The first time this happened a few months ago I changed the sprite (just by duplicating it and changing its name). Today changing the sprite didn't solve the issue. Today's solution was to duplicate the entire PType (I have 2 emitters that were using the same Ptype). I saved the PType preset and applied it to the second emitter. The color animation on the Ptype didn't get saved :o( so I copied the animation from the original ptype to the duplicate. The pass is now rendering more than 2 frames again from the command line.