Draggable problem with Safari?

Hello,
I have such code:
<div style="width: 600px !important; height: 600px;
background-image: url(http://foo);" id="powierzchnia">
<div id="postac" style="width: 116px; height: 291px;"><img
src="http://foo.png" alt="obraz" style="width: 116px; height: 291px;" /