I had someone in the LS have the same issue, when they upgraded to Windows 8. We found that the issue was related to not having files present. Specifically Windower 4/addons/libs/
following were not present:
xml.lua
vectors.lua
timeit.lua
texts.lua
tablehelper.lua
stringhelper.lua
slips.lua
sets.lua
resources.lua
readme.md
packets.lua
matrices.lua
mathhelper.lua
luau.lua
logger.xml
logger.lua
lists.lua
json.lua
functools.lua
filehelper.lua
ffxidata.json
ffxi.lua
config.lua
colors.lua
chat.lua
Also check ...addons/libs/resources for:
I suggest checking to see if you are missing any of these. Cause all that it took was sending them the files to make it work.