[NTG-context] need help for the installation of luatools

Hi, all, I have downloaded binary files(lua5_1_2_Darwin89_bin_tar). After unzip, there are 3 files "bin2c5.1, lua5.1, luac5.1". I copied lua5.1 as luatex and texlua in the folder /usr/texbin. I also copied luatools.lua as luatools in the folder /usr/texbin. I updated the ConTeXt and try to install LuaTeX. But, I got an error as following when I issue "luatools". apple: dalyoung$ luatools texlua: /usr/texbin/luatools:4183: attempt to index global 'lua' (a nil value) stack traceback: /usr/texbin/luatools:4183: in main chunk [C]: ? I am using TeXlive installed with i-installer. Please give me some hints to avoid the errors. Thank you. Best regards, Dalyoung