Yay! Found a "bug"! (or rather...denial of use...)
See, if you have an in-battle event where a party member is added (he comes to the rescue after 10 turns, or something), the battle HUD won't add him.
Like, let's say Aluxes must fight 3 turns before Basil (Add Party Member in Battle) comes in to help, you'd see Aluxes' Hud on the bottom. However, when Basil comes in, his HUD doesn't and as a result, the next time Basil will take action, RTAB will crash with this line.
script "RTAB" line 3687: NoMethodError occured
undefined method "refresh" for nil:NilClass
I know you ain't RTAB's creator or anything, but I figured you'd be the best person to let that know.