I have tested this in the latest version of firefox, ie9, ie8, the latest version of Chrome with no problems.

The only thing I can think of is that you may already some javascript or jquery installed in your cart that conflicts or there was a mistake in integrating or installing this mod.

Stoyka, since you had it installed before, would you give me the url of your website? You can pm me if you want. I want to look at what else is installed.

Y'all have to understand that I am no javascript expert by any imagination so may not be able to figure this out unless I can duplicate the problem on a correct installation.