floated sortables don't work right in IE

floated sortables don't work right in IE

I've heard of others having this problem before, but I can't seem to find a solution. I have a page of floated div tags that the user can drag and drop in whatever order they want. The problem I'm having is that when the user clicks on the div and begins to drag it, the div shifts down to the bottom of the page, so it is no longer visible. I did not have this problem with scriptaculous, but jQuery is so much faster that I would prefer to use it if I can. I attempted to search the forum, but didn't find anything, so sorry if this has been answered before. Thanks!

Here is an example link of what I'm trying to do:

http://www.mtnstatessupply.com/members/example.html

and the CSS for those divs are:

.card { position:relative; float:left; width:30%; border:1px solid black; padding:3px; margin:3px; }

It works fine with all browsers I've tried, except Internet Explorer. Removing "float:left" from the CSS makes it so it works, but then they aren't floated, obviously.