Can't call activex methods when the activex is in the same page as flash player

Question

I created a customized ActiveX control and exposed a method called "getDesktopWindows". Then I use the following javascript to call it:

var plugin = document.getElementById("myPlugin"); var wins = plugin.getDesktopWindows();

So far everything works just fine. Then I wrapped the code into a javascript function and use a flex application to call it.

// in javascript

function getDesktopWindows() { var plugin = document.getElementById("myPlugin"); var wins = plugin.getDesktopWindows(); return wins; }

// in flex

var wins = ExternalInterface.call("getDesktopWindows");

Now I'll receive "Microsoft JScript runtime error: Object doesn't support this property or method"

Guessing the problem would be because the call is originated from flash player. I tryed call it directly in javascript. And again I received the same exception. So may it because there're two activex present in the same webpage?