Maybe I’m focussing on the wrong problem, but the flicking on a frame by frame basis from one set of pictures to another smacks of a persistent disk cache error. I’d be quite surprised if it wasn’t that. What your video shows couldn’t happen if the emitter layer were moving erratically, because the particles are jumping from frame to frame too. An erratically moving camera couldn’t cause the effect if your text layer is also 3D.
I would seriously try emptying the disk cache again from the preferences and then immediately purging the RAM cache under the edit menu. The trick is to flush everything from cache simultaneously. If you flush the disk cache, but not the RAM, the disk cache is re-established wrongly from the RAM and vice-versa. I would be inclinded to turn disk cache off under the preferences.
Another alternative is to add another effect to the layer… for instance a gentle Tint. This will also serve to invalidate the disk cache as it currently stands.
Make sure you have the timeline cache indicators turned on and keep a careful eye on what they’re doing.
If that still doesn’t work, then back-save from CS6 to CS5.5 or CS5. There’s no point going back to CS4, as you’ll have to reconstruct your project manually.
Let us know if and how you solve it.