Please see http://dragissue.stefanvanroon.nl/index.html
In the left col you see images (yes, all the same), you can drag these to the sortable list on the right.
So, you click on an image from the left col, drag it to the sortable list (don't drop), now you drag the element back to the left col and there are the errors is get in IE.
http://dragissue.stefanvanroon.nl/assets/js/mootools/more-uncompres... @ line 6752
if (options.style) this.element.setStyle(options.modifiers[z], this.value.now[z] + options.unit);
(I'm sorry if this is not so clear, it's hard to explain for a Dutch-guy)
This is a mootools-more issue.