i have the same problem with bgiv2 game,
extracting them can be done with AE, but they are a raw data, not an image or readable script text...
the tools from tlwiki only decompile script from bgiv1, and not compatible with bgiv2,
btw, i already search and wandering online and i found this:
https://github.com/xupefei/BGIKit
https://github.com/marcussacana/EthornellEditor
but none of those 2 support bgiv2...
i already ask someone from aokana tl disscussion as well, but no reply yet...
edit: i found this tools, says can extract data from bgi game, but since its only avaiable as source code i dont know what to do with this, i'am not a programmer...
https://github.com/minirop/arc-reader