Passing an external object

Hello,

I got an object into a class (a public one) called “squaddie0”, and when i try to call it back from another class dynamically with :

the main_class is the passed class, i get the vars like this : main_class.var1
var index:int = 0;
var ob:Object = (getDefinitionByName(main_class[“squaddie”+index]) as Object;

I get an error as an undefined object…
Why that ?

thanks again