I’m not sure what’s going on here, but I’m using 1.4.1 jQuery and 1.8rc1 jQueryUI and the base theme works, but when I switch to any other theme everything is broken. I just downloaded the themes from the link in this post: http://jquery-ui.googlecode.com/files/jquery-ui-themes-1.8rc1.zip

Here’s some links so you can diagnose:
Base Theme:
http://www.realestatehomepages.com/livedevpropertysearch/index.asp?p=105658&i=10805

Just change the link at the end to insert a theme:
http://www.realestatehomepages.com/livedevpropertysearch/index.asp?p=105658&i=10805&SelectedTheme=redmond