I also had an "N/A" effect set in CCSM/Effects/Animations/Focus Animation. Instead of deleting the entry completely, I just assigned an available effect (Fade) instead of N/A and re-enabled Animations afterwards. I dunno what I had set before I upgraded to 12.04, but it seems the previous effect was removed and so it became N/A? I know for sure from multiple testing in the past days - when I disabled the Animations Effect completely, then the problem was gone. If this change of teh Focus Animation on its own would fix it as well then its very likely that this was the cause.
I also had an "N/A" effect set in CCSM/Effects/ Animations/ Focus Animation. Instead of deleting the entry completely, I just assigned an available effect (Fade) instead of N/A and re-enabled Animations afterwards. I dunno what I had set before I upgraded to 12.04, but it seems the previous effect was removed and so it became N/A? I know for sure from multiple testing in the past days - when I disabled the Animations Effect completely, then the problem was gone. If this change of teh Focus Animation on its own would fix it as well then its very likely that this was the cause.