I had the same error with Might and Guile in BWS. I checked the code and realized it was due to a kit installed previously called Grizzly Bear, which had the last entry duplicated in kitlist.2da, effectively creating a new column. I deleted the duplicated kitids and Might and Guile installed properly.Grizzly Bear is the official kit entry made for Wilson. It is vanilla contents.
There are at least two mods in BWS that could have changed that: Wilson chronicles, and The Bear Walker - a Werebear/Ranger kit. Maybe one of these could have duplicate the entry in kitlist.2da.
Also, is there a way to install mods compatible with an EET install listed in K4thos' list that doesn't show in BWS, such as Pai'Na NPC?
If its EET compatible you can install it manually after. Just keep in mind that mods that need to reference .DLG files might fail to install due to the .DLGs being altered when EET_end runs.
You shouldn't have any problems installing Pai'Na though.