I also would love to get rid of those annoying warnings. Meanwhile (v8 dailies), even CoronaSelect map works perfectly as input for Bercorn tiles. The reason for the warning is just because it tends to crash (like it always did) afaik - if you have "show shaded material in viewport" active for the map/material. Additionally you can still always crash it by deleting a bitmap node from Multitexture while IR is running.Good Luck@Marcin: ticket #192300
IR crashes on my usage quite often as well...