Authentic

in normal kro exists two clients ragexe and ragexeRE.
in zero client named ragexe too. but it related only for ragnarok zero server.
with hercules you can use one of this clients. Grf need use for same server from where you get client. Simplest way it install kro and use oficial updater or rsu to update it to latest version. Then download unpacked exe and patch it.
If you want one of old versions, here is harder. need find full client version bit older than you selected and apply all missing updated.
You may have different errors with lua or other files. Try search forums about this errors or ask in irc or discord.
 

supporter clients kro: ragexe, ragexeRE
kro zero: ragexe
 

I apparently don't have a comprehensive understanding of a modern Ragnarok Client, i would love to have an explanation or link to somewhere that does (Believe me I've tried searching closest stuff I've found isn't in English)

So I've gotten ragexe2016 stuffs to work just fine, but we want to update to a newer client or experiment with one of the RagREexes (I always thought these were for Renewal servers but I've pieced together their apparently not their for Sakray and have a better interface...right?) 
SO.... Maybe i'm in over my head but i'm really trying to learn this because my kids want to learn about this stuff and its a little pet project to get them into some higher levels of computer stuffs. i'm trying to help them and i haven't done Ragnarok in years and not only has a lot changed, I've forgotten more then i can remember. 

so i tried working with Some of the newer clients to date (2018-07-04aRagexe.exe and 2018-07-11aRagexeRE.exe) and i keep getting errors about null values with the ragexeRE, and the Ragexe 

so i know the errors i get are " gettableintvalueforc Attempt to call a nil value"
i understand that its Lua related and i honestly haven't a clue how to fix it (yes im using an Updated KRO and Zach's Trans Pack ) is there anyone out there that point me in the right direction on what i have to do to get the right files here? 
OR is the unpacked EXEs that i'm using too new? if thats so whats the latest versions that will work?
I know that is a lot of questions.... But thank you for the help i'll continue beating my head against the wall and make stabs in the dark in the mean time lol