.animate() issue with IE9 and jquery 1.3.2

.animate() issue with IE9 and jquery 1.3.2

I am having some recent trouble with a Drupal 6 site and IE9. My script.js contains several functions, so I guess the issue could be a conflict, but I don't think it is. The function that is breaking in IE9 (only) is the following:

  1. function animateOverlay() {
  2.     $("#overlay").animate({    "height": "+=50px" }, 2000, function() { $("#thumbnails").animate({ "height": "+=40px"    }, 2000)});
  3. }

It should be very straightforward, but in IE9, the elements contained in #thumbnails disappear after being animated. What more troubling is that only some of the elements will disappear. I am happy to file a bug if this is one, but I'm still trying to understand more about what's happening. The site is still live, despite the issue. Have a look here and thanks for your feedback.