I copied lua5.1 as luatex and texlua in the folder /usr/texbin.
That's not what you should do: lua5.1 is only the lua interpreter, nothing more, and cannot act as LuaTeX (the TeX engine with embedded Lua scripting). Nor can it act as TeXLua, the LuaTeX-aware Lua interpreter. Of course both lua5.1 and texlua are Lua interpreters and this is why luatools superficially works; but the latter has more libraries than lua alone, one of them called 'lua': luatools cannot work without those. What you should do is take the Mac binary for *LuaTeX* and copy it under the different names (texlua and texluac); symlinks are fine, too. Recent binaries are available at http://foundry.supelec.fr/frs/?group_id=10 as both Intel Mac and universal binaries (no PPC-alone binary, sorry). That way, you actually don't need Lua itself (everything you need is built-in into LuaTeX). One you've done that, you can start over again. Feel free to ask questions if you have other problems. Arthur