Google for Firefox

Ok folks,

Somehow, I have lost my google toolbar for firefox, and I can not re-install it. I keep getting an error message saying- unexpected installation error. could not install file at http://dl.google.com/firfox/google-toolbar-win.xpi - Any help at all would be greatly appreciated. I have tried uninstalling,rebooting reinstalling....everything. When I down load it and restart firefox, it is not in my extentions....I keep getting the above error. Don't know what to do?

Thanks
ranrae