XPCOM component

Hi everybody,

I'm a software developper and I work on Mac OS X 10.3. I'm trying to  
develop a Mozilla extension (.XPI file) which use a costum Gecko  
embedded Mozilla components. I access to this component with  
JavaScript file.

The extension work well during one session.

fellowing this steps, the extension work well.
-Install the extension (xpi files)
-Close Firefox
-Reopen FireFox

Note:
In "console.log" I can see the registration of the component.(***  
Registering MyClass components (all right -- a generic module!))

But if I close Firefox and reopen it, the extension does not work  
correctly.
The extension fail during instanciation of the component.

I think that problem is the registration of the component. I verify  
if there is unregistration of the component when Firefox is closing  
but it seem not.

I will appreciate if someone can give me a hint
Regards

Pierre.