jQuery Frame Animation plugin doesn't work in FireFox 4.0

http:/开发者_StackOverflow/demo.dev.bitami.com/jQuery/frameanimation/demo.html

This doesn't work in FF 4.0

I get:

Warning: Error in parsing value for 'background-position'. Declaration dropped. Source File:

Please let me know if you can open it and how to fix it if it's to be fixable.

Thanks

Edit:

It seems like firefox doesn't like [space] as value in the position attribute:

obj.css("backgroundPosition", "0px " + offset + "px");

What can i replace it with or escape it perhaps?

The problem was with
obj.css("backgroundPosition", "0px " + offset + "px");

It has to be:
obj.css('background-position', ('0px ' + offset + 'px')); in order to work in Firefox 4

I have posted the whole code here (with some other minor changes):

http://forum.jquery.com/topic/jquery-frame-animation-plugin-and-firefox-4