Dear Hans, Thank you for the reply. Here is the codes of luatools.lua from line number 1106 - %%%%%%%%%%%%%%% 1106: if md5 then do 1107: local function convert(str,fmt) 1108: return (string.gsub(md5.sum(str),".",function(chr) return string.format(fmt,string.byte(chr)) end)) 1109: end if not md5.HEX then function md5.HEX(str) return convert(str,"% 02X") end end if not md5.hex then function md5.hex(str) return convert(str,"% 02x") end end if not md5.dec then function md5.dec(str) return convert(stt,"% 03i") end end end end %%%%%%%%%%%%% Since most people didn't have the problem in installation. it reminded me a problem when I installed the XeTeX a long time ago. After installed files of XeTeX, I tried to make a format, but I couldn't succeed. I reported the error message to XeTeX mailing list, but every one had no problem to install and to make a format. They said that it was good in their system. Finally Jonathan found that it was related with my OSX(OSX korean version) even though I put english at the top priority in the preference panel. He installed korean in his system to locate the problem and removed the problems. Is this problem related with my OSX? I hope that the line 1108 gives you a clue of my problem. Thank you. Best regards, Dalyoung