Dealing with lua in asterisk 1.6

Asterisk Asterisk Support
1

Hi

I’m trying to use lua with asterisk 1.6 beta 5. I’ve tried to make working a simple extension but it doesn’t work. it always returns me this message :

pbx_lua.c:1131 exec: Error executing lua extension: attempt to call a nil value

here is my extensions.lua :

function demo_test()
app.noop(“test”)
end

extensions = {
customer = {
[“7777”] = demo_test;

    };

    default = {
            ["7777"] = demo_test;
    };

}

do you have any idea of what could be the problem ?