Following kokeeby's steps did not work for me. I did everything to the T to no avail and I get "could not load text." So when I specified the path ways all I get is a black screen then crashes as a result when I place Fallout 1 files critter.dat and master.dat files into the "data folder," inside BISmapper folder, but if I put them into separate folders Critter.dat files in Critters folder and Master.dat files in Master folder inside the Data folder for example it loads. If I place Fallout 1 maps into BISmapper's custom maps folder I'm able to open and edit them, but nothing else works right referring to the scripts, and so on. BISmapper will not load off of folders it needs the file itself to run.
So I have a question... If Fallout 2's Critter.dat and Master.dat files were modified with Fallout 1's Critters, Protos, Scripts, Maps, Sounds, Texts, etc would BISmapper be able to load info properly then?
If so what files of Fallout 2 would at least need to be kept inside the Critter.dat and Master.dat?