Hi Mark
on Safari 2.0.4 with Tiger, when the image hasn't loaded, the activity window shows a "too many http redirects" error message.
EDIT - Whilst I am certainly just blundering in the dark a bit, some brief research shows that Safari can be more prone to these errors, and that often, changing the Browser User Agent makes the error go away, which is no help directly to you. Soo, a thought anyway, your page uses some javascripts hosted on another site eg
http://yui.yahooapis.com/2.3.1/build/event/event-min.js - If it's easy for you to copy these to the same server as the rest of the page/images - I'd give it a try.