Thread:Extension talk:Scribunto/Lua error: Internal error: The interpreter exited with status 126./reply (3)

I had exactly the same problem until I made Scribunto/engines/LuaStandalone/lua_ulimit.sh executable. Once I did that, it worked great.

Setting  to a file name I could write to pointed out I was getting execute permission denied on that file. What does your log file say?