Firefox javascript problems

I use Firefox 1.0.4:
In one site, the drop down menus dont apperar. I suppose it is javascript problem.
I see a lot of errors in the javascript console such as:

Error: _drawMenu is not defined
Source File: http://img.abv.bg/ns/menu/menu_src.js
Line: 2

and

Error: closeAllMenus is not defined
Source File: http://img.abv.bg/ns/104/js/abvmenu.js
Line: 9

and

Error: popup is not defined

and

Error: popdown is not defined

Moreover:
Javascript popups appear as new tabs!!!!
(for example: in /www.spywareinfoforum.com/ -> "My assistant" or in games.yahoo.com)

I also have problem with this message window. Firstly I couldnt write in it!!! And i dont know how now i can?!?!

The problems appeared after i scan and fix with Ccleaner and RegSeeker and after the installation of Avast.

With Opera 8.01 everything considering javascript works fine!

Please help me!
I am desperate! I even preinstall Firefox but it didnt work!

 

Please post the site.

 

I uninstalled Firefox 1.0.4 and preinstalled it and the problem is gone!